C-12 TRUCK ENGINE Caterpillar

P-1.0 Electronic System Overview

Usage:

System Operation

The C-10, C-12, 3406E, C-15 and C-16 Truck Engines are designed for electronic control. The injection pump, fuel lines and nozzles used in mechanical engines have been replaced with an electronic unit injector in each cylinder. A solenoid on each injector controls the amount of fuel delivered by the injector. An Engine Control Module (ECM) sends a signal to each injector solenoid to provide complete control of the engine.

Electronic Controls

The electronic system consists of the Engine Control Module (ECM), Engine Sensors and Vehicle Interface. The ECM is the computer which controls the engine. The Personality Module in the ECM contains the software which controls how the ECM behaves (the personality module stores the operating maps that define power, torque curves, rpm, etc).

Engine Governor

The Electronic Controls on the engine serve as the engine governor. The Electronic Controls determine when and how much fuel to deliver to the cylinders based on the actual and desired conditions at any given time.

The governor uses the Accelerator Pedal Position Sensor to determine the desired engine speed and compares this to the actual engine speed determined through the engine Crankshaft Position Sensor. If desired engine speed is greater than the actual engine speed, the governor injects more fuel to increase engine speed.

The desired engine speed is typically determined by the position of the accelerator pedal, desired vehicle speed when in cruise control, or desired engine rpm when in PTO control.

Timing Considerations

Once the governor has determined how much fuel is required, it must next determine when to inject the fuel. Injection timing is determined by the ECM after considering input from the Coolant Temperature Sensor, Intake Manifold Air Temperature Sensor, Atmospheric Pressure Sensor, and Boost Pressure Sensor.

The ECM determines where top center on cylinder number one is located from the engine Camshaft Position Sensor signal. The ECM decides when injection should occur relative to top center and provides the signal to the injector at the desired time. The ECM adjusts timing for best engine performance, fuel economy and white smoke control. Actual or Desired Timing cannot be viewed with an Electronic Service Tool.

Fuel Injection

The ECM controls the amount of fuel injected by varying signals to the injectors. The injectors will pump fuel only if the injector solenoid is energized. The ECM sends a high voltage signal to energize the solenoid. By controlling the timing and duration of the high voltage signal, the ECM can control injection timing and the amount of fuel injected.

The Personality Module inside the ECM sets certain limits on the amount of fuel that can be injected. FRC Fuel Limit is a limit based on boost pressure to control the air/fuel ratio for emissions control. When the ECM senses a higher boost pressure (more air into cylinder), it increases the FRC Fuel Limit (allows more fuel into cylinder).

Rated Fuel Limit is a limit based on the power rating of the engine and rpm. It is similar to the rack stops and torque spring on a mechanically governed engine. It provides power and torque curves for a specific engine family and rating. All of these limits are determined at the factory in the Personality Module and cannot be changed.

Customer Parameters Effect on Engine Governing

A unique feature with Electronic Engines is Customer Specified Parameters. These parameters allow the truck owner to fine tune the ECM for engine operation to accommodate the typical usage and power train of the vehicle.

Many of the Customer Parameters provide additional restrictions on the action the ECM will take in response to the drivers' input. For example, the PTO Top Engine Limit is an rpm limit the ECM uses as a cutoff for fuel. The ECM will not fuel the injectors above this rpm.

Some parameters are intended to notify the driver of potential engine damage (Engine Monitoring Parameters). Some parameters enhance fuel economy (Vehicle Speed, Cruise Control, Engine/Gear Limits and Idle Shutdown Parameters). Other parameters are provided to enhance the engine installation into the vehicle or provide engine operating information to the truck owner.

Engine Monitoring

Caterpillar provides a factory installed Engine Monitoring system. The Caterpillar Engine Monitoring system monitors engine oil pressure, coolant temperature, intake manifold air temperature, and coolant level (optional, OEM installed).

The Oil Pressure, Intake Manifold Air Temperature, and Coolant Temperature Sensors are standard on all engines. The Vehicle OEM installs the coolant level sensor and the associated harness. The Coolant Level Sensor is the only optional component of Caterpillar Engine Monitoring. It is selected through a Customer Programmable Parameter.

Caterpillar Engine Monitoring can be programmed to four different modes (OFF, WARNING, DERATE, and SHUTDOWN). The Coolant Temperature, Oil Pressure and Coolant Level (if selected) Sensors will operate in the Engine Monitoring Mode selected.

For example, if DERATE mode was selected, the engine will derate engine power and vehicle speed if the Coolant Temperature, Oil Pressure or Coolant Level (if selected) Sensors detect conditions exceeding acceptable limits.

An excessive Intake Manifold Air Temperature will not derate or shut down the engine.

Caterpillar Engine Monitoring OFF

If Caterpillar Engine Monitoring is programmed to OFF, the ECM will not flag low oil pressure, high coolant temperature, and low coolant level. No warnings will occur if conditions are exceeded which could cause the ECM to take Engine Monitoring action.

The ECM still uses these sensors for normal engine operation, such as the Coolant Temperature Sensor for Cold Mode operation.

Caterpillar Engine Monitoring WARNING Operation

If the system is programmed to WARNING, the ECM causes the Warning Lamp to turn ON, and will also cause the Check Engine Lamp to Flash (because of the Active Diagnostic Code) to indicate a problem has been detected by the Engine Monitoring System. No further ECM or engine action occurs if the ECM is programmed to WARNING.

Caterpillar Engine Monitoring DERATE Operation

If the system is programmed to DERATE, the ECM begins by flashing or activating the Warning Lamp ON, and the Check Engine Lamp will flash to indicate a problem has been detected by the Engine Monitoring System. If the problem is due to a Low Coolant Level, Low Oil Pressure, High or Very High Intake Manifold Air Temperature condition, the ECM will cause the Warning Lamp to turn ON and the Check Engine Lamp to flash as mentioned for WARNING Mode.

When oil pressure becomes Very Low Oil Pressure, coolant level becomes Very Low Coolant Level, or coolant temperature becomes High or Very High Coolant Temperature, DERATE Mode begins by flashing the Warning Lamp. Whenever the Warning Lamp is FLASHING, the ECM is limiting (derating) the engine.

For High and Very High Coolant Temperature, or Very Low Coolant Level, the ECM limits the maximum vehicle speed and reduces available power. If the detected condition is Very Low Oil Pressure, vehicle speed, power and engine rpm are limited.

This derating of engine performance is provided to get the drivers' attention so action can be taken to avoid engine damage.

Caterpillar Engine Monitoring SHUTDOWN Operation

If the system is programmed to SHUTDOWN the ECM takes all the action indicated for the DERATE Mode and will eventually shut down the engine under some conditions.

When oil pressure becomes Very Low Oil Pressure, coolant level becomes Very Low Coolant Level, or coolant temperature becomes Very High Coolant Temperature, SHUTDOWN Mode begins by flashing the Warning Lamp the same as DERATE. SHUTDOWN Mode will eventually cause the engine to shut down if the conditions continue long enough, and are severe enough.

Illustration 1 - Engine Monitoring Coolant Temperature Start/Restart Graph

Illustration 2 - C-10, C-12 Engine Monitoring Coolant Temperature Graph

Illustration 3 - 3406E, C-15 & C-16 Engine Monitoring Coolant Temperature Graph

Illustration 4 - Engine Monitoring Coolant Level Graph

Illustration 5 - Engine Monitoring Coolant Level Time Graph

Illustration 6 - C-10, & C-12 Low Oil Pressure Graph (JUL99 and older Personality Modules)

Illustration 7 - C-10, & C-12 Low Oil Pressure Graph (OCT99 and newer Personality Modules)

Illustration 8 - 3406E, C-15 & C-16 Low Oil Pressure Graph

Illustration 9 - Very Low Oil Pressure Start-Up/Restart Graph

Fuel Temperature Monitoring

The Fuel Temperature Sensor monitors the fuel temperature, adjusting the ECM calculated fuel rate to compensate for fuel temperature changes and to adjust the fuel rate for constant power. The sensor is also used to warn the operator of excessive fuel temperature with a Diagnostic Event Code because excessive fuel temperatures can adversely affect engine performance. An Electronic Service Tool can be used to temporarily disable Fuel Temperature adjustment when necessary for testing a vehicle on a dynamometer with fuel temperature compensation.

Other ECM Performance Functions

The ECM also provides enhanced control of the engine for vehicle functions such as engine retarding and cooling fan control. The illustration "C-10, C-12, 3406E, C-15 & C-16 Component Diagram" on page 17 shows many of the OEM systems the ECM can monitor to provide enhanced vehicle performance, fuel economy and driver convenience.

Self-Diagnostics

The electronic system has the ability to diagnose problems. When a problem is detected, a diagnostic code is generated and the Diagnostic/Check Engine lamp may be turned ON. In most cases, the code is also stored in permanent memory (Logged) in the ECM.

When diagnostic codes occur, they are called Active. They indicate a problem of some kind currently exists. They should always be serviced first. If a truck is brought in with an Active Code, find the code in the front of this manual and proceed to the indicated page to diagnose the cause.

Diagnostic codes stored in memory are Logged. Since the problem may have been temporary or may have been repaired since the time it was logged, logged codes do not necessarily mean something needs to be repaired. They are instead meant to be an indicator of probable causes for intermittent problems.

Diagnostic Codes that identify operating conditions outside of the normal operating range are called Events. Event codes are typically are not an indication of an electronic system problem.

Some of the codes require passwords to clear. Codes not requiring passwords to clear are automatically deleted from memory after 100 Engine operating hours.

Engine Snapshot Data

Whenever most diagnostic codes occur, the ECM records the time (in engine hours), as well as engine operating parameters for 9.6 seconds before and 3.4 seconds after the diagnostic code. The engine operating parameters recorded are similar to those in the Electronic Technician status screens. Not all Electronic Technician status screens or parameters are recorded.

The Engine Snapshot can also be triggered from the Cruise Control Set/Resume switch (quickly toggling the switch to Set and then to Resume or Resume to Set), or from the Electronic Technician.

Diagnostic Codes Effect on Engine Performance

The discussion on Engine Monitoring mentions the Check Engine Lamp flashes when a specific condition exists. When the ECM detects the engine problem, it generates an Active Diagnostic Code and also Logs the code to indicate when, and if appropriate, how many times the problem occurs. There are two types of Diagnostic Codes-Fault Codes and Event Codes.

Diagnostic Fault Codes are provided to indicate an electrical or electronic problem has been detected by the ECM. In some cases the engine performance can be affected when the condition causing the code exists. More frequently, however, the driver cannot detect any difference in the engine performance.

If the driver indicates a performance problem occurs whenever the Check Engine Lamp is flashing, the Diagnostic Code may indicate the cause of the problem, and should be corrected.

If the driver does not indicate a problem with the engine performance and a Diagnostic Code is logged by the ECM, it indicates the ECM detected an abnormal condition, but it did not affect performance.

If this is the case, unless there are several occurrences of the code in a very short period of time, or, the ECM is indicating an Active Code at the present time, there is most likely nothing wrong with the system.

Diagnostic Event Codes are provided to indicate some operational problem has been detected in the engine or truck by the ECM. This usually does not indicate an electronic malfunction.

The ECM also provides an ECM Clock with Date/Time to date and time stamp the following critical event codes:

* 84-00 Vehicle Overspeed Warning (41)

* 84-14 Quickstop Occurrence (00)

* 100-11 Very Low Oil Pressure (46)

* 105-11 Very High Intake Manifold Air Temp. (64)

* 110-11 Very High Coolant Temperature (61)

* 111-11 Very Low Coolant Level (62)

* 190-00 Engine Overspeed Warning (35)

This manual contains a table listing all of the PID-FMI Diagnostic codes, along with the page number where details regarding the cause, performance affect, and troubleshooting of the code can be located.

The table "PA-12: Possible Performance Effect of Active Diagnostic Codes" on page 64 lists all C-10, C-12, 3406E, C-15 and C-16 Diagnostic Codes, and whether each code may or may not affect engine performance.

Current Totals Stored In The ECM

The ECM maintains engine total data for the following parameters.

* Total Time is engine running hours (it does not include time when the ECM is powered ON without the engine running).

* Total Distance data requires a vehicle speed sensor/source connected to the ECM (the same sensor used for ECM vehicle speed). Distance can be displayed in miles or kilometers.

* PTO Time and PTO Fuel are logged with engine rpm is set using the Cruise switches and the engine is operating under some load or when the Dedicated PTO On/Off Switch is ON, and vehicle speed is within range of the PTO Vehicle Speed Limit Parameter.

* Idle Time and Idle Fuel can include time when the engine speed is set using the Cruise switches and the vehicle speed is within range of the Idle Vehicle Speed Limit Parameter, but the engine is not operating under load. Fuel information can be displayed in US Gallons or liters.

* Average Load Factor provides relative engine operation information (how hard the engine has been operated compared to the maximum), determined using Total Max Fuel, Idle Fuel and Fuel used.

* Total Fuel is the total amount of fuel the engine has used.

* Total Max Fuel is the maximum fuel the engine can use during operation.

Trip Data Stored In The ECM

Trip data allows the owner of the vehicle to track engine operation over owner defined intervals. Two types of Trip Data are stored in the ECM, Driver Trip Data and Fleet Trip Data. All of the Trip Data is stored in memory and maintained through the Unswitched Battery connections when the ignition key switch is OFF. An internal battery will maintain this information while the Unswitched Battery connections are disconnected.

Driver Trip Data

Driver Trip Data is known as the Driver Trip Segment. The Driver Trip Segment includes Total Time, Distance, Fuel, Idle Time, Idle Fuel, PTO Time, PTO Fuel, Average Load Factor, Average Vehicle Speed, Percent Idle Time, Percent PTO Time, and Overall Fuel Economy, Driving Fuel Economy, Driving Time, Average Driving Speed, Maximum Vehicle Speed, Maximum Engine Speed, Start Time, End Time, Start Odometer, End Odometer.

A Driver Trip Segment can be reset using an Electronic Service Tool or a Caterpillar Driver Information Display (CAT ID).

When the data is reset, the ECM stores the Current Totals for the engine at the time of the reset for use as the Driver Trip Data starting point. The Service Tool or CAT ID accesses this start point and the Current Data Totals from the ECM to calculate the Driver Trip Segment Data. Resetting the Driver Trip Segment does not require passwords.

Fleet Trip Data

Fleet Trip Data includes a Fleet Trip Segment, Histograms, and Custom Data. The Fleet Trip Segment records the same parameters as the Driver Trip Segment, except it can be reset independently of the Driver Trip Segment.

Three histograms are available. The first histogram records engine operation time versus engine speed, the second records engine operation time versus vehicle speed, and the third records engine operation time versus engine speed and vehicle speed.

The Electronic Service Tool calculates the percentage of time spent in each of the engine rpm or vehicle speed ranges. Custom Data is available allowing the ECM to record engine parameters specified by the vehicle owner.

A reset of the Fleet Trip Data (includes Fleet Trip Segment, Histograms, and Custom Data) can be done in several ways. An Electronic Service Tool (may require Customer Passwords), Caterpillar Fleet Information Software (FIS), or the CAT ID (requires Customer Parameter) may all reset the Fleet Trip Data.

When the data is reset, the ECM records the Lifetime Data Totals for the engine at the time of the reset for use as the Fleet Trip starting point. The Electronic Service Tool, Caterpillar Fleet Information Software (FIS), or CAT ID accesses the start point recorded and then subtracts it from the current Lifetime Data Totals in the ECM to calculate the Fleet Trip Data. Resetting the Fleet Trip Data requires Customer passwords.

Fleet Trip Custom Data

Fleet Trip Custom Data is part of the Fleet Trip Segment. It allows the owner of the vehicle to set five customized methods of recording data for the vehicle.

The basic program is SUM____________________¹ FOR____________________² BETWEEN____________________³ AND____________________⁴ AND____________________⁵ BETWEEN____________________⁶ AND____________________⁷.

Variable 1 can be Engine Hours, Distance Traveled-(kilometers or miles)_, Fuel Burned-(liters or gallons), or Occurrences-(number of times event occurs).

Variables 2 through 7 are as indicated in the following table.

Below is an example of a Custom Data program.

Fuel Burned when Fuel Temperature is between 45 and 120 Deg F and Vehicle Speed is between 55 and 85 MPH.

The Custom Data programs are Customer Password protected. The programs are stored in permanent memory. The programs are not reset when the Fleet Trip Segment is reset, but the data recorded for the Trip is reset.

Fuel Correction Factor

A Customer Password protected Fuel Correction Factor is available for fine tuning fuel consumption calculations. This can be used to enhance the accuracy of the fuel used calculation.

Altering the Fuel Correction Factor does not affect data already stored in the ECM, only data stored after the Fuel Correction Factor is entered.

NOTE: The Fuel Correction Factor should be adjusted based on a long interval, using actual tank data and the ECM recorded data.

Quick Stop Rate

A Customer Parameter is available to record "Quick Stop" occurrences. The Parameter determines the rate of vehicle speed change the ECM uses to record a Quick Stop Event Code and Quick Stop Snapshot. Refer to "Quick Stop Rate" on page 52 for a description of the parameter, and "Quick Stop Snapshot" on page 32 for a description of the data stored in a Quick Stop Snapshot.

Maintenance Indicator Data

The ECM records the Lifetime Data Totals when a maintenance reset occurs for three levels of maintenance - PM1, PM2, and Coolant Flush/Fill.

The previous maintenance point is used by the ECM to calculate when the next maintenance is due.

The Maintenance Indicator feature is programmable to hours of distance. The PM1 maintenance is programmable to Off, Automatic-Distance, Automatic-Hours, Manual-Distance, or Manual-Hours.

If PM1 is programmed to automatic, the ECM calculates the next maintenance due by considering the vehicle operation history from the previous maintenance interval. If the vehicle has a history of poor fuel economy, the maintenance indicator will occur sooner than a vehicle with better fuel economy.

The ECM also uses the Engine Oil Capacity, with a larger capacity providing a longer maintenance interval. Engine Oil Capacity is programmed in liters (or quarts). If the PM1 Maintenance Indicator is programmed to Manual, the owner can program in their own specific maintenance mileage or time interval. PM2 and Coolant Flush/Fill intervals are determined by the factory.

CAT ID

The Caterpillar Driver Information Display (CAT ID) is available to provide operating information to the driver about the engine. The Driver Trip Segment, Fleet Trip Segment, and Maintenance Indicator can be viewed. However, the Fleet Trip Segment Histograms and Custom Data cannot be viewed from the display.

CAT ID provides the ability to enter a driver identification (ID) to divide the Fleet Trip Segment for two drivers. The Fleet Trip Segment can also be tagged by state, if the driver enters state crossings.

In summary, the CAT ID can be used to tag portions of the Fleet Trip Segment into two driver ID's and into states as required. The driver ID and state by state information cannot be viewed from the display, only Caterpillar Fleet Information Software (FIS) can view this information. The ability to reset any of these parameters is dependent on Customer Parameters in the ECM.

CAT ID will also display engine operating parameters such as engine rpm, coolant temperature, boost pressure, etc, as well as engine diagnostic codes with the PID-FMI and a brief text description.

An available feature of CAT ID is Theft Deterrent. Theft Deterrent allows the driver to input a four character password prior to engine shutdown and prevent the engine from restarting until the four character password is re-entered. The CAT ID must have the software version capable of supporting this feature.

With OCT99 and newer Personality Modules an additional Theft Deterrent option is available called Auto-Enable. When the Theft Deterrent Parameter is programmed to the Auto-Enable option, the theft deterrent system is automatically enabled at each engine shutdown. In order to start the engine, the correct password must be entered.

The OCT99 and newer Personality Modules also offer the Secure Idle feature that limits the engine to low idle until the theft deterrent password is re-entered. To enter the Secure Idle mode, the engine must be brought to an idle condition and then the Theft Deterrent password entered. The engine will then remain at low idle (no response to accelerator pedal) until the password is re-entered.

Fleet Information Software (FIS)

Caterpillar Fleet Information Software (FIS) is another method to review the trip information. The entire Fleet Trip Segment, including Histograms, Custom Data, and information tagged by driver ID and by state can all be accessed. Maintenance Indicator information can also be accessed using the Caterpillar FIS.

When Caterpillar FIS downloads the information it also resets the ECM to prepare it for the next trip. The information can be downloaded to a computer with the Caterpillar FIS program, or to an Argo Mobile Data Tool (MDT) which is then connected to a computer to download the information.

Driver Reward Feature

The Driver Reward Feature automatically adjusts the VSL as a reward to the driver for operating a truck in a manner meeting the truck owner's specifications. Several parameters are monitored in order to evaluate a drivers operating habits. Weighting factors are applied to the parameters reflecting the desired and expected operating habits. If operating habits meet or exceed the owner's specifications, the VSL is automatically increased as a reward. The VSL will decrease when operating habits do not meet owner specifications.

The CAT ID can be used to monitor parameters affecting the Driver Reward, allowing the driver to adjust operating techniques as required.

Wireless Communication Enable

The ECM Wireless Communication Enable parameter allows the ECM to interact through the SAE J1587 Data Link with certain communication systems. Programming this parameter requires Factory Passwords.

With this system the customer can remotely change the following parameters using Cat FIS:

* Fuel Correction Factor

* Custom Data Parameters

* Maintenance Indicator Parameters

With this system the customer can remotely extract the following information from the ECM:

* Current Totals

* Custom Data Reports

* Fleet Trip Information

* Economy Model

* Maintenance Information

* Customer Parameter Settings

The reports are all processed for the fleet owner using Cat FIS. The frequency and timing of the information download can be at set intervals or manual.

Programmable Parameters

Certain parameters affecting engine operation may be changed with electronic service tools. The parameters are stored in the ECM, and are protected from unauthorized changes by passwords. These parameters are either "System Configuration Parameters" or "Customer Parameters".

System Configuration Parameters are set at the factory and affect emissions or power ratings within a family of engines. Factory Passwords must be obtained and used to change System Configuration Parameters.

Customer Parameters are variable and can be used to affect cruise control, vehicle speed limits, progressive shifting, rpm/power ratings within the limits set by the factory, Caterpillar Engine Monitoring, and PTO operation. Customer Passwords may be required to change Customer Specified Parameters.

Some parameters may affect engine operation in ways a driver does not expect. Without adequate training, these parameters may lead to power or performance complaints, even when the engine is performing to specification.

Refer to section "P-3.0 Programmable Parameters" on page 38 for more details.

Passwords

"System Configuration Parameters" are protected by Factory Passwords. Factory passwords are calculated on a computer system available only to Caterpillar dealers. Since factory passwords contain alphabetic characters, only an electronic service tool may change System Configuration Parameters. System Configuration Parameters affect power family or emissions.

"Customer Parameters" can be protected by Customer Passwords. The customer passwords are programmed by the customer. Factory Passwords can be used to change Customer Passwords if they are lost.

Refer to section "P-3.0 Programmable Parameters" on page 38, for more details when passwords are needed and how to obtain them.

C-10, C-12, 3406E, C-15 & C-16 Component Diagram