3512E Tier 4 Final Engines for 785G Off-Highway Trucks Caterpillar


Dosing Control System Operation

Usage:

785G RTL

General Operation

Table 1
Single Clean Emission Module Aftertreatment System 
DEF Pump  DEF Injectors  DEF Pressure Line Color 
2, 3  Blue 
1, 4  Green 


Illustration 1g06169473
The illustration depicts only 1 DEF dosing system. There are 2 DEF dosing systems for this application (both are identical).
(1) Exhaust inlet
(2) Inlet nitrogen oxide (NOx) sensor
(3) Diesel Exhaust Fluid (DEF) injector
(4) Catalyst brick
(5) Outlet NOx sensor
(6) Exhaust out
(7) DEF supply line
(8) Coolant return to engine line
(9) DEF pump
(10) Coolant supply from engine line
(11) Coolant diverter valve
(12) DEF backflow valve
(13) DEF tank
(14) Coolant supply connector
(15) Suction connector
(16) Backflow connector
(17) Coolant return connector
(18) DEF suction line
(19) DEF backflow line
(20) Diesel Exhaust Fluid Control Unit
(21) Selective Catalyst Reduction Controller

The purpose of Diesel Exhaust Fluid (DEF) is to create a reaction across the Selective Catalytic Reduction (SCR) catalysts to reduce nitrogen oxides (NOx).

When the engine is keyed on but not running, DEF is not being injected into the system. When the engine is running, the DEF may be too cold or frozen to be injected. When the ambient or tank temperatures are cold enough, the Diesel Exhaust Fluid Control Unit (DCU) opens the coolant diverter valve to allow engine coolant to flow through the DEF tank to warm the system. The DCU also activates the heater circuits in the lines to prevent DEF from freezing in the lines and pump. The time it takes to thaw the system depends on the ambient temperature.

Once the system is thawed and primed, the DEF will be injected into the exhaust system when the exhaust temperatures are warm enough. If the system does not heat up after duration of time, a diagnostic code will become active.

Note: Typical usage for DEF is 1-3% of diesel fluid. The DEF tank is sizedto be refilledat the same time as the fuel tank.

The DEF system has three operation modes:

1. DEF Priming Mode

Since the system always starts with empty lines, the pump activates to fill the lines with fluid before DEF injection begins. Priming will start when engine speed is at idle, DEF tank temp is greater than −6° C (21.2° F), and SCR inlet temperature is greater than 180° C (356° F). Once the system reads the appropriate pressures, priming is complete.

2. DEF Injection Mode

Once the system is primed, the DEF will be injected when SCR inlet temperature is greater than 250° C (482° F). The DEF pump draws DEF from the tank and pressurizes the DEF to 900 kPa (130.5 psi). This pressure is constant throughout the operating cycle. The DEF injectors spray DEF into the exhaust before the SCR catalyst. The DEF injection rate is controlled by changing the duration of the DEF injector on time. The DEF injector is controlled by a PWM signal. If the engine is producing higher NOx, the DEF injector will be open for a longer duration, allowing more DEF into the exhaust stream. To control the pressure to the DEF injector, a percentage of DEF will flow through the backflow line (controlled by the back flow valve) back to the tank.

3. DEF Purge Mode

When certain DEF fault codes become active or the engine is keyed OFF, the DCU enters purge mode. The system is designed to purge all DEF back to the DEF tank to prevent it from freezing in the pump and lines. The DEF injector opens and the DEF Reverting valve in the DEF pump reverses the flow of the DEF. This removes the DEF from the pressure line and pumps it back to tank through the suction line. The purge takes approximately 2 minutes to remove DEF from the lines and pump. It is important NOT to turn off the battery disconnect switch during the purge process. If the purge process does not complete and the temperature of the DEF drops below −11° C (12° F), then the pump and lines are at risk of damage. If the purge process does not complete a diagnostic code will become active.

NOx Monitoring

There are four NOx sensors supplied with the engine. Two NOx sensors are installed in the exhaust inlet from the turbocharger (engine out). The other two NOx sensors are installed in the exhaust pipe of the application (CEM out).

The amount of DEF needed is based on NOx production. The engine produces NOx as the engine operates at a specific target to meet emission requirements. The engine out NOx sensors measure the amount of NOx in the exhaust stream at the inlet to the CEM. The tailpipe out NOx sensors monitor the NOx level out of the catalyst. Based on the engine out and the tail pipe out NOx sensor values, the flow rate of DEF will adjust to meet the NOx allowed per regulations.

NOx Sensors



Illustration 2g06183118
(22) Electrical connector
(22) Sensor electronic control unit
(24) Cable (black for engine out, gray for CEM out)
(25) Sensing unit

The NOx sensor contains a sensing element, a harness, and an electronic control unit. The sensing element is composed of two chambers and a heater. The first chamber measures the amount of oxygen and the second chamber measure the amount of NOx and Ammonia (NH3). Using electrochemistry, a ceramic material attracts ions at approximately 800° C (1472° F) and an electrode on the chamber wall measures the electrical charge in voltage or current. The voltage or current signal is then received by the NOx sensors electronic control unit and interpreted into a NOx concentration. The heater is used to maintain the sensing element temperature, as sensing element is sensitive to moisture. If the sensor sees any moisture while at 800° C (1472° F), then the moisture could quickly cool the element which would cause the element to crack. At engine start-up there is always some moisture within the exhaust pipes. So the sensors will not start working until the exhaust temperature around the sensors is greater than 100° C (212° F) for approximately two and a half minutes. The NOx sensor has a 12,000-hour maintenance interval.

Note: For information on handling the NOx sensors, refer to Special Instruction, REHS8151.

Electric Components



Illustration 3g06169511
Pump Electronic Tank Unit (PETU)
(26) DEF pump 1
(27) Coolant diverter valve for pump 2 system
(28) DEF header for pump 1 system
(29) Electrical connection for DEF header 2
(30) Coolant diverter valve for pump 1 system
(31) Electrical connection for DEF header 1
(32) DEF header for pump 2 system
(33) Backflow valve for pump 1 system
(34) DEF pump 2
(35) Backflow valve for pump 2 system


Illustration 4g06169505
(36) DEF Pump 2 Line Heater #7 Connection Point (Pressure Line from Pump to Injector Y Connection)
(37) DEF Pump 1 Line Heater #2 Connection Point (Pressure Line from Pump to Injector Y Connection)
(38) DEF Pump 1 Line heater #1 (Backflow Line from DEF Pump to Backflow Valve )
(39) DEF Pump 1 Line heater #3 (Suction Line)
(40) DEF Pump 1 Line heater #4 (Backflow Line from Backflow Valve to DEF Header)
(41) Voltage Limiting Protection Module (VLPM)
(42) Voltage Limiting Protection Module (VLPM)
(43) Line heater relay #1
(44) Line heater relay #2
(45) DEF Pump 2 Line heater #9 (Backflow Line from Backflow Valve to DEF Header)
(46) DEF Pump 2 Line heater #8 (Suction Line)
(47) DEF Pump 2 Line heater #6 (Backflow Line from DEF Pump to Backflow Valve )


Illustration 5g06169506
(43) Line heater relay #1
(44) Line heater relay #2
(48) DCU 1
(49) Line heater relay #5
(50) Aftertreatment ECM
(51) DCU 2
(52) Main power relay

The Pump Electronics Tank Unit (PETU) consists of the following components:

Coolant Diverter Valve

Controls coolant flow to the tank and DEF pump for DEF tank and DEF pump heating.

Power Relays

The main power relay is for the entire PETU.

Line heater relay #1 controls the line heater for the DEF pump #1.

Line heater relay #2 controls the line heater for DEF pump #2.

Line heater relay #5 controls the line heater for the ground level fill hose, the ground level fill receiver, and the DEF tank fill valve assembly on the PETU tank.

Diesel Exhaust Fluid Control Unit (DCU)

The DCU controls all of the functions related to the pumping and injection of DEF into the exhaust stream.

Heated Lines

The heated lines are electrically heated lines that will turn on any time ambient temperature and DEF tank temperature are below a threshold. The heated lines will also stay heated during operation in cooler ambient conditions to prevent any freezing during operation.

Voltage Line Protection Module (VLPM)

Protects all electrical components from voltage spikes.

DEF Pump



Illustration 6g06169527
(53) 100 micron screen
(54) Inlet port
(55) Coolant inlet
(56) Coolant outlet
(57) Backflow
(58) Outlet port
(59) Main DEF filter

The pump supplies filtered DEF fluid to the DEF injector. The pump consists of an inlet port (54) which is the suction side of the pump that draws DEF from the DEF tank. The pump then pressurizes the fluid up to 896 kPa (130 psi) and supplies the fluid though outlet port (58).

Once the engine is shutdown, the pump will start to go into a purge mode. The DEF Injector will open and the reverting valve within the pump will reverse the flow of the pump and purge the pump and pressure line. This reversed flow will route any remaining DEF fluid back to the tank through the inlet port (54).

The DEF inlet connector has a 100 micron screen (53) to filter any debris that may come in from the DEF tank. The connector is serviceable.

The main DEF filter (59) filters the DEF coming into the pump before going out the back flow and outlet lines. The DEF filter is serviceable and has a 4,500-hour maintenance interval. Refer to Operation and Maintenance Manual for the correct procedure to replace the DEF filter.

Engine coolant is routed through the pump during cold-weather operation.

The DEF pressure sensor is located inside of the DEF pump and monitors the pressure of the DEF in the dosing system. This sensor is not serviceable, the sensor is part of the DEF pump.

DEF Tank Header



Illustration 7g06169537
(60) DEF tank header filter (32 micron) (If equipped)
(61) DEF level sensor (float)
(62) Coolant tubes
(63) DEF tank temperature sensor (integrated with DEF level sensor, not shown)
(64) DEF tank header filter (100 micron)

The DEF tank header is located in the DEF tank. The tank header consists of several parts and performs the following functions:

DEF Level Sensor

There is a tank level sensor to measure the amount of usable DEF in the tank. The level sensor includes a flotation device that contains a magnet. As the fluid level changes, the float slides along a shaft that a series of reed switches and resistors. There are multiple reed switches for different heights of the tank. The magnetic float closes the passive reed switch and completes the circuit of resistors giving a different resistance output. The DCU then interprets the resistance to a tank level and changes the DEF gauge. The tank level sensor will send a signal to the DCU to signal that the level of DEF is low. The engine may derate and a fault code will become active if the level of DEF is below a critical level.

DEF Pickup Tube

The DEF is pulled from the bottom of the tank through a screen.

DEF Tank Header Screen

At the end of the DEF Pickup tube is a 100 micron screen to filter debris from entering the system. The screen is a serviceable part and has a 6,000 hour service maintenance interval.

DEF Tank Header Filter

A 32 micron filter wraps around the coolant tubes to filter debris from entering the pickup and backflow circuits. The DEF manifold filter is serviceable and has a 6,000 hour service maintenance interval.

Coolant Tubes

The coolant supplied by the engine will flow through the tubes when the coolant diverter valve opens. Coolant runs along the pickup tube to the bottom of the tank and then spirals around the level sensor. The heat from the coolant will thaw any frozen DEF in the tank or header. The heat will also prevent the DEF from freezing around the pickup tube.

DEF Backflow Tube

The pump has a backflow circuit to return DEF back to the tank. The backflow tube returns the DEF to the top of the tank.

DEF Tank Temperature Sensor

At the bottom of the tank header near the DEF tank header screen is a tank temperature sensor. This sensor monitors the temperature of the DEF in the tank. This temperature is used to determine when to turn on the coolant diverter valve.

DEF Injector



Illustration 8g06169540
(65) Coolant return port
(66) DEF Supply line
(67) Electrical Connector
(68) Coolant supply port

The DEF injector is mounted to the Clean Emissions Module (CEM). The DEF injector is a valve that injects DEF as a fine spray into the exhaust stream as an atomized mist. The spray pattern being conical for good mixing with the exhaust is critical.

The tip of the injector, that is located in the exhaust flow, is cooled by coolant that flows through an internal coolant passage from the engine coolant supply. The injector can become damaged when exposed to high temperatures so it is important to keep the injector cooled. The coolant flow, as well as the DEF injection process, provides the cooling capability needed to protect the injector.

High temperatures at engine shutdown can exceed the hardware limit of the DEF injector and damage the injector tip. To protect the injector from high temperature at engine shutdown, the "Delayed Engine Shutdown" (DES) strategy will run for a time after the engine start switch key is turned to the OFF position. This strategy allows the engine to continue running to prevent high exhaust temperatures from damaging the DEF injector at engine shutdown. Once the exhaust temperatures are below a threshold, the injector is cooled and the engine will shutdown.

Some applications may use an Injector Coolant Tank (ICT) instead of DES to protect the DEF injector. The ICT provides a reservoir of coolant above the injector which keeps the injector cooled so that high exhaust temperatures at engine shutdown will not damage injector. Coolant boils at the injector and vapor travels up into ICT while liquid coolant from ICT backfills coolant lost to boiling. Energy lost to boiling helps to maintain injector temperatures below hardware limits.

DEF Backflow Valve



Illustration 9g06059218

The DEF backflow valve is installed in between the DEF pump backflow line and the DEF header to help maintain proper pressure in the DEF system while injection is taking place. The DEF backflow valve is controlled by a PWM signal. The DEF backflow valve is a normally closed valve that is commanded to open.

Cold-Weather Operation



Illustration 10g06169861
(69) Coolant diverter valve for pump 2 system
(70) Coolant diverter valve for pump 1 system
(71) DEF header (heater only)
(72) DEF header

Since DEF freezes at −11° C (12° F), the system must thaw DEF before dosing during operation in cold ambient temperatures. Engine coolant is supplied to the PETU. The coolant diverter valve will turn on anytime the DEF tank temperature is less than 15° C (59° F) at engine start-up. During operation, if the DEF tank temperature drops below 20° C (68° F) or ambient temperature falls below 0° C (32° F) then the coolant diverter valve will activate to keep the DEF from freezing. The tubes running through the tank will thaw the DEF to a usable temperature. DEF injection will occur once the DEF has been thawed and the DEF tank temperature is greater than −6° C (21° F). The coolant will flow through the DEF pump to warm the pump. The coolant will then return to the engine water pump inlet. The DEF supply lines, suction lines, and backflow lines are heated electrically. DEF injection will occur once the system has determined there is enough DEF thawed in the tank to maintain DEF injection into the exhaust stream.

Note: If DEF has not been removed from the lines and pump during cold-weather operation, the DEF will expand as the fluid freezes and damage the lines and pump. The purge process will take 2 minutes of run time and must complete. The purge process may occur during Delayed Engine Shutdown. It is important not to turn off the battery disconnect switch during the purge process. Do not turn off the battery power disconnect switch until battery disconnect switch indicator lamp has turned off. If the purge process does not complete, a diagnostic code will become active.

Coolant Diverter Valve



Illustration 11g06169867
(73) Flow direction indicator

The coolant diverter valve is a normally closed valve. The valve is a unidirectional flow valve. The system is used for warming the DEF tank before dosing will occur. Warming the system is achieved by taking warm coolant from the engine and routing the coolant through the tank and DEF pump. The coolant diverter valve will open when the tank temperature needs to be increased. Once the DEF tank temp is warm enough, the system will start dosing.

Heated Lines



Illustration 12g03037439

Even though the system has been purged of DEF there are small quantities of DEF that can be left behind. The DEF supply line, suction, and the back flow line are heated to thaw any remaining DEF in the lines. The heated lines will prevent restrictions in the pump and injector once the system begins to dose.

  • Thermoplastic core tube with fabric reinforcement

  • Stainless steel heating wire

  • Extruded thermoplastic jacket

  • Heat/abrasion shield

Operator Level Inducement

Inducement is defined as something that helps bring about an action or a desired result. The purpose of inducements is to prompt the operator to repair or perform maintenance on the emissions control system.

Inducement strategies are control actions required by EPA/ARB Tier 4 final and European Union (EU) Stage IV regulations to ensure prompt correction of various failures in the engine NOx emissions control system. They require actions to limit engine performance and define required indications such as visual alarms including lamps and messages, as well as audible alarms, while the control actions are imposed. The times for lights, derates, and alarms will vary between EPA and EU.

The inducements are initiated by the engine ECM. Inducements include derates and forced idle down or shutdown. When the engine derates, the rpm and torque are reduced.

Note: Operator Inducement Service Mode Override can be used to override the inducements so the equipment has full power. Factory passwords are required to activate this override.

Programmable parameters to select different Inducements options



Illustration 13g03365820

  • Engine Emissions Operator Inducement Regulation Configuration

Engine Emissions Operator Inducement Regulation Configuration



Illustration 14g03365830

This programmable parameter will define the emissions regulation that the engine will follow in the event an inducement becomes active. The location of the engine must be considered before selecting this parameter. The "Worldwide" configuration may be used in any region of the world and will be emissions-compliant. The "European Union" may only be selected if the engine will operate in Europe. Once the "European Union" configuration is selected, the unit cannot go back to "Worldwide". If used outside of this region the engine will not be emissions-compliant. Only a select number of industrial engines will be allowed to select "European Union" configuration. All machine engines will be configured for "Worldwide".

Safe Harbor Mode (Worldwide)

Safe Harbor Mode (Worldwide) is a 20 minute engine run time period that the engine can be operated with full power after reaching a level 3 inducement. Once in level 3 inducement, the operator can perform a key cycle and the engine will enter Safe Harbor Mode. The safe harbor mode can be used to move the machine to a location where the machine can be serviced. If 20 minutes of engine running time has passed and the fault has not been corrected, the engine will reach final inducement with derates until the fault has been fixed. Safe Harbor Mode can only be implemented once. Safe Harbor Mode is not allowed for DEF level inducements with Worldwide configuration.

Safe Harbor Mode (European Union)

Safe Harbor Mode (European Union) is a 30 minute engine run time period that the engine can be operated with full power after reaching a level 3 inducement. Once in level 3 inducement, the operator can perform a key cycle and the engine will enter Safe Harbor Mode. The safe harbor mode can be used to move the machine to a location where the machine can be serviced. If 30 minutes of engine running time has passed and the fault has not been corrected, the engine will reach final inducement with derates until the fault has been fixed. Safe Harbor Mode can only be implemented up to three times.

Engine Emissions Operator Inducement Service Mode Override



Illustration 15g03365844


Illustration 16g03365848

Engine Emissions Operator Inducement Service Mode Override allows a technician to service inducement-related faults on a machine while having full engine operation and no derate effects. This mode is initiated through a connection with Cat ET. This mode requires a factory password to activate. Engine Emissions Operator Inducement Service Mode Override can be entered as many times as necessary and does not have a time limit. However, if Cat ET loses connection, the Override will automatically turn off. The Cat ET "Engine Emissions Operator Inducement Service Mode" is located in the "Diagnostic Tests", "System Troubleshooting Section" of the engine ECM.

The Inducements are separated into the following categories: DEF Quality, Tampering, SCR System Fault, and DEF Level. The "Emissions Malfunction Indicator Lamp" will illuminate if any fault codes in these categories become active. The system reaction is varied based on the category of the fault code and what inducement parameters are selected.

DEF Quality: The system has detected bad DEF Quality. The concentration of urea does not meet the ISO standard for DEF.

Tampering: The system has detected a failure that was caused by tampering with emissions components. This could include the removal or modifications to engine or emissions components.

DEF Level: The DEF Tank Level is low. If the DEF tank becomes empty, the system is not capable of meeting emissions.

SCR System Fault: The emissions components or system has a failure and can no longer meet emissions.

Service Tests Which Override Inducements

There are several service tests which will be allowed to run while inducements are active. Service tests provide the ability to diagnose and fix the issue that led to inducement without the use of factory passwords. While these tests can always be run on machines, not all industrial applications will be able to run service tests while inducements are active. In those cases, the Engine Emissions Operator Inducement Service Mode Override with factory passwords will need to be used.

Service Test that Override Inducements:

  • Aftertreatment System Functional Test

Inducement Strategy for DEF Level (Worldwide)



Illustration 17g06180865
(74) DEF Level Gauge: This gauge shows the amount of DEF in the DEF tank.
(75) DEF Level Gauge Amber lamp: This amber lamp indicates the DEF level is low.
(76) Check Engine Lamp (CEL): This lamp activates for all engine and aftertreatment faults that affect the engine.
(77) Emissions Malfunction Indicator Lamp (EMIL): This lamp activates for all emissions faults that trigger inducement strategy.
(78) Action Lamp: For machine engines only, this lamp indicates a Level 2 or Level 3 fault is active.
(79) Red Stop Lamp: For industrial engines only, this lamp indicates a Level 3 fault is active. Symbol may vary.
(80) Audible Alarm: For Machines, the alarm sounds when a Level 3 fault is active.

Low DEF Level Warning



Illustration 18g03523436

If the DEF level falls below 20%, the DEF level gauge amber lamp will illuminate. To avoid inducements, turn the key to the OFF position and add DEF to the DEF tank.

Level 1 Inducement



Illustration 19g03523619

If the DEF level falls below 18%, the engine will be in level 1 inducement. A 1761-17 or E954 (1) Aftertreatment #1 Diesel Exhaust Fluid Tank Level : Low - least severe (1) diagnostic code will become active. The check engine lamp (CEL) and emissions malfunction indicator lamp (EMIL) will illuminate solid. The DEF level gauge amber lamp will continue to illuminate.

Level 2 Inducement



Illustration 20g03523621
The action lamp will not illuminate for industrial applications.

If the DEF level is below 12.5%, the engine will be in level 2 inducement. A 1761-18 or E954 (2) Aftertreatment #1 Diesel Exhaust Fluid Tank Level : Low - moderate severity (2) diagnostic code will become active. The DEF level gauge amber lamp, CEL, and EMIL will remain lit. For machines, the CEL and EMIL will remain solid. For industrial applications, the CEL and EMIL will begin to flash slowly. For machines only, the action lamp will illuminate and flash. If the ECM is configured to "Reduced Performance" and the DEF level has reached 1%, the machine will have a 50% derate.

Level 3 Inducement



Illustration 21g03523622
Industrial applications, will use the STOP lamp and not an action lamp. There is no audible alarm for industrial application.

If the ECM is configured to "Reduced Performance" and the DEF tank has been emptied of all DEF, the engine will be in a level 3 final inducement. If the ECM is configured to "Reduced Time" and the DEF level is 7.5%, the engine will be in a level 3 final inducement. When in level 3 inducement, a 1761 -1 or E954 (3) Aftertreatment #1 Diesel Exhaust Fluid Tank Level : Low - most severe (3) diagnostic code will become active. For machines only, an audible alarm will begin to sound 20 seconds prior to the level 3 inducement. The DEF level gauge amber lamp, CEL, and EMIL will remain lit. For machines, the CEL and EMIL will remain solid and the action lamp will continue to flash. For industrial applications, the CEL and EMIL will flash at a faster rate and a red stop lamp will illuminate solid. The engine will have a 100% derate and be limited to 1000 rpm or low idle, whichever is greater. If the final inducement action in Cat ET is set to "Idle Down", then engine will continue to idle at derated condition. If set to "Shutdown", engine will shutdown after 5 minutes. The engine may be restarted, but will only run for 5 minutes at derated condition before shutting down again. This action will continue until the issue is resolved.

Note: Turn the key to the OFF position and add DEF to the DEF tank to reset the DEF level inducement.

Inducement Strategy for DEF Quality, Tampering, and SCR System Fault (Worldwide)

Level 1 Inducement



Illustration 22g03523624

The CEL and EMIL will illuminate solid for a fault resulting from poor DEF quality, SCR system tampering, SCR system fault, or an EGR system fault. If the fault is the result of poor DEF quality, SCR system tampering, or SCR system fault, a first occurrence will result in a level 1 inducement for a duration of 2.5 hours. When in level 1 inducement, a 5246 -15 or E1389 (1) Aftertreatment SCR Operator Inducement Severity (1) diagnostic code will become active. Repeat occurrences will result in a level 1 inducement duration of 5 minutes.

Level 2 Inducement



Illustration 23g03523637
The action lamp will not illuminate for industrial applications.

If a fault condition exists for the entire duration of inducement level 1, the strategy advances to inducement level 2. When in level 2 inducement a 5246 -16 or E1389 (2) Aftertreatment SCR Operator Inducement Severity (2) diagnostic code will become active. The CEL and EMIL will remain lit. For machines, the CEL and EMIL will remain solid. For industrial applications, the CEL and EMIL will begin to flash slowly. For machines only, the action lamp will illuminate and flash. For poor DEF quality, SCR system tampering, and SCR system faults, the duration for a level 2 inducement is 70 minutes for the first occurrence. Repeat occurrences will result in a level 2 inducement of 5 minutes.

Level 3 Inducement



Illustration 24g03523639
Industrial applications, will use the STOP lamp and not an action lamp. There is no audible alarm for industrial application.

If a fault condition exists for the entire duration of inducement level 2, the strategy advances to inducement level 3. When in level 3 inducement a 5246 -0 or E1389 (3) Aftertreatment SCR Operator Inducement Severity (3) diagnostic code will become active. For machines only, an audible alarm will begin to sound 20 seconds prior to the level 3 inducement. For machines, the CEL and EMIL will remain solid and the action lamp will continue to flash. For industrial applications the CEL and EMIL will flash at a faster rate and a red stop lamp will illuminate solid.

The engine will have a 100% derate and be limited to 1000 rpm or low idle, whichever is greater. If the final inducement action in Cat ET is set to "Idle Down", then engine will continue to idle at derated condition. If set to "Shutdown", engine will shutdown after 5 minutes. A key cycle will allow safe harbor mode to kick in. Safe harbor is only allowed once. After safe harbor, the engine will be in level 3 final inducement. If set to "Shutdown", the engine may be restarted, but will only run for 5 minutes at derated condition before shutting down again. This action will continue until the issue is resolved.

Note: Contact your Cat dealer for repairs if a fault occurs.

Inducement Strategy for DEF Level (European Union)



Illustration 25g06180865
(74) DEF Level Gauge: This gauge shows the amount of DEF in the DEF tank.
(75) DEF Level Gauge Amber lamp: This amber lamp indicates the DEF level is low.
(76) Check Engine Lamp (CEL): This lamp activates for all engine and aftertreatment faults that affect the engine.
(77) Emissions Malfunction Indicator Lamp (EMIL): This lamp activates for all emissions faults that trigger inducement strategy.
(78) Action Lamp: For machine engines only, this lamp indicates a Level 2 or Level 3 fault is active.
(79) Red Stop Lamp: For industrial engines only, this lamp indicates a Level 3 fault is active. Symbol may vary.
(80) Audible Alarm: For Machines, the alarm sounds when a Level 3 fault is active.

Low DEF Level Warning



Illustration 26g03523436

If the DEF level falls below 20%, the DEF level gauge amber lamp will illuminate. To avoid inducements, turn the key to the OFF position and add DEF to the DEF tank.

Level 1 Inducement



Illustration 27g03523619

If the DEF level falls below 18%, the engine will be in level 1 inducement. A 1761-17 or E954 (1) Aftertreatment #1 Diesel Exhaust Fluid Tank Level : Low - least severe (1) diagnostic code will become active. The CEL and EMIL will illuminate solid. The DEF level gauge amber lamp will remain lit.

Level 2 Inducement



Illustration 28g03534876

Reduced Performance

When the ECM is configured to "Reduced Performance" and the DEF level is below 1%, the engine will be in level 2 inducement. A 1761-18 or E954 (2) Aftertreatment #1 Diesel Exhaust Fluid Tank Level : Low - moderate severity (2) diagnostic code will become active. The CEL and EMIL will illuminate and flash slowly. The DEF level gauge amber lamp will remain lit. The engine will have a 50% derate. When the DEF tank has been emptied of all DEF, the engine will have a 100% derate and be limited to 1000 rpm or low idle, whichever is greater. No further inducement action will occur for "Reduced Performance" configuration. Safe Harbor Mode is allowed for 3 key cycles.

Reduced Time

When ECM is configured to "Reduced Time" and the DEF level is below 12.5%, a 1761-18 or E954 (2) Aftertreatment #1 Diesel Exhaust Fluid Tank Level: Low - moderate severity (2) diagnostic code will become active. The CEL and EMIL will illuminate and flash slowly. The DEF level gauge amber lamp will remain lit.

Level 3 Inducement



Illustration 29g03523637
Industrial applications will use the STOP lamp and not an action lamp

Reduced Time

If the ECM is configured to "Reduced Time" and the DEF level is 0%, a 1761 -1 or E954 (3) Aftertreatment #1 Diesel Exhaust Fluid Tank Level : Low - most severe (3) diagnostic code will become active. The CEL and EMIL will illuminate and flash at a fast rate. An action lamp or red stop lamp will illuminate solid. The DEF level gauge amber lamp will remain lit. The engine will have a 100% derate and be limited to 1000 rpm or low idle, whichever is greater. If the final inducement action in Cat ET is set to "Idle Down", then engine will continue to idle at derated condition. If set to "Shutdown", engine will shutdown after 5 minutes. Safe Harbor Mode is allowed for 3 key cycles. After Safe Harbor Mode is completed, the engine will return to idle or shutdown. If in shutdown configuration, the engine may be restarted, but will only run for 5 minutes at derated condition before shutting down again. This action will continue until the issue is resolved.

Note: Turn the key to the OFF position and add DEF to the DEF tank to reset the DEF level inducement.

Inducement Strategy for DEF Quality, Tampering, and SCR System Fault (European Union)

Level 1 Inducement



Illustration 30g03523624

Reduced Performance

The CEL and EMIL will illuminate solid for a fault resulting from poor DEF quality, SCR system tampering, SCR system fault, or an EGR system fault. If the fault is a result of poor DEF quality or SCR system fault, a level 1 inducement will occur for a duration of 10 hours. If the fault is the result of SCR system tampering, a level 1 inducement will occur for 36 hours. When in level 1 inducement, a 5246 - 15 or E1389 (1) Aftertreatment SCR Operator Inducement Severity (1) diagnostic code will become active.

Reduced Time

The CEL and EMIL will illuminate solid for a fault resulting from poor DEF quality, SCR system tampering, SCR system fault, or an EGR system fault. If the fault is a result of poor DEF quality or SCR system fault, a level 1 inducement will occur for a duration of 5 hours. If the fault is the result of SCR system tampering, a level 1 inducement will occur for 18 hours. When in level 1 inducement, a 5246 - 15 or E1389 (1) Aftertreatment SCR Operator Inducement Severity (1) diagnostic code will become active.

Level 2 Inducement



Illustration 31g03523624

Reduced Performance

If a fault condition exists for the entire duration of inducement level 1, the strategy advances to inducement level 2. When in level 2 inducement a 5246 -16 or E1389 (2) Aftertreatment SCR Operator Inducement Severity (2) diagnostic code will become active. The CEL and EMIL will flash slowly. For poor DEF quality and SCR system faults the duration for a level 2 inducement is 10 hours for the first occurrence. Repeat occurrence will result in level 2 inducement for 2 hours.

The engine will have a 50% derate. If the fault is not corrected before the inducement duration ends, the engine will become 100% derated and be limited to 1000 rpm or low idle, whichever is greater. No further inducements will occur for "Reduced Performance" configuration. Safe Harbor Mode is allowed for 3 key cycles.

Reduced Time

If a fault condition exists for the entire duration of inducement level 1, the strategy advances to inducement level 2. When in level 2 inducement a 5246 -16 or E1389 (2) Aftertreatment SCR Operator Inducement Severity (2) diagnostic code will become active. The CEL and EMIL will flash slowly. For poor DEF quality and SCR system faults the duration for a level 2 inducement is 5 hours for the first occurrence. Repeat occurrence will result in level 2 inducement for 1 hour. For SCR system tampering and EGR system faults, the duration for a level 2 inducement is 18 hours for the first occurrence. Repeat occurrence will result in level 2 inducement for 1 hour 48 minutes.

Level 3 Inducement



Illustration 32g03523637
Industrial applications will use the STOP lamp and not an action lamp

Reduced Time

If configured to "Reduced Time" and a fault condition exists for the entire duration of inducement level 2, the strategy advances to inducement level 3. When in level 3 inducement a 5246 -0 or E1389 (3) Aftertreatment SCR Operator Inducement Severity (3) diagnostic code will become active. The CEL and EMIL will flash at a fast rate. An action lamp or red stop lamp will also illuminate solid.

The engine will have a 100% derate and be limited to 1000 rpm or low idle, whichever is greater. If the final inducement action in Cat ET is set to "Idle Down", then engine will continue to idle at derated condition. If set to "Shutdown", engine will shutdown after 5 minutes. A key cycle will allow safe harbor mode to kick in. Safe harbor is allowed up to three times. After safe harbor, the engine will be in level 3 final inducement. If set to "Shutdown", the engine may be restarted, but will only run for 5 minutes at derated condition before shutting down again. This action will continue until the issue is resolved.

Note: Contact your Cat dealer for repairs if a fault occurs.

Caterpillar Information System:

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