814F Series 2 Wheel Dozer, 815F Series 2 Soil Compactor and 816F Series 2 Landfill Compactor Power Train Caterpillar

Neutral Start Function

Illustration 1	g00329538
Start Relay

The start relay is an output of the power train electronic control module (ECM). The start relay turns the start solenoid on and off. The start solenoid controls the starting motor. When the operator turns the key start switch to the START position and the power train ECM decides that all the starting conditions are satisfied, the power train ECM energizes the start relay with a +battery signal. The power train ECM will not allow the engine to be started unless the transmission direction control switch is in the NEUTRAL position. If the transmission direction control switch is in the NEUTRAL position, the power train ECM activates the start relay. The start relay allows the starting motor to turn. The power train ECM will not allow the starter to activate if the engine is running.

The start relay has a connector with two contacts. One contact receives power from connector contact J1-8 of the power train ECM. The other contact returns power to connector contact J2-3 of the power train ECM.

Terminal 3 of the start relay connects to a +battery source. Terminal 4 connects to the start solenoid.

ReferenceFor more information on the key start switch, refer to the Service Manual module Systems Operation, "Input Components" for the machine that is being serviced.

ReferenceFor more information on the power train electronic control module (ECM), refer to the Service Manual module Systems Operation, "Electronic Control Module (Power Train)" for the machine that is being serviced.

Manual Shift Function

Note: The 814F/F Series 2 has four forward speeds and four reverse speeds. The 815F/F Series 2 has three forward speeds and three reverse speeds. The 816F/F Series 2 has two forward speeds and two reverse speeds.

Illustration 2	g00876961
(1) Transmission direction and speed control lever

Illustration 3	g00876964
(2) Transmission downshift switch

Shifting the transmission is the main function of the power train electronic control module (ECM). The power train ECM interprets the changes in the switch position. After the power train ECM interprets the changes in the switch position, the power train ECM shifts the transmission.

Transmission direction and speed control lever (1) is a sealed unit. The transmission direction and speed control lever is mounted on the steering column. The transmission direction and speed control lever allows the operator to select a speed range by rotating the control lever. The operator can select a direction by moving the transmission direction and speed control lever forward or backward. The transmission will remain in the selected direction until the transmission direction and speed control lever is moved forward or backward. The transmission will remain in the selected speed until the transmission direction and speed control lever is rotated to a different speed.

If second speed forward or second speed reverse are selected, the transmission will shift to first speed by depressing upshift/downshift switch (2). The transmission will remain in first speed until one of the following actions takes place.

• The transmission direction and speed control lever (1) is shifted into the opposite direction.

• The upshift/downshift switch is depressed again.

• The transmission direction and speed control lever (1) is shifted into the NEUTRAL position.

When the key start switch is turned from the OFF position to ON position, the power train ECM is activated. When the power train ECM is first activated all of the clutch solenoid modulating valves are de-energized. The clutch solenoid modulating valves are de-energized regardless of the position of transmission direction and speed control lever (1). The power train ECM then determines if the transmission direction and speed control lever is in the NEUTRAL position. The power train ECM disables the transmission if the NEUTRAL position is NOT selected. If the NEUTRAL position is NOT selected, the transmission direction and speed control lever must be returned to the NEUTRAL position before a direction can be selected. The power train ECM activates the start relay and the power train ECM allows the engine to start if the transmission direction and speed control lever is in the NEUTRAL position. The power train ECM allows the initial selected speed to be changed if the transmission direction and speed control lever is in the NEUTRAL position.

Note: Transmission direction and speed control lever (1) must be in the NEUTRAL position when the key start switch is turned to the START position. If the transmission direction and speed control lever is not in the NEUTRAL position, the start relay will not be activated when the key start switch is turned. For additional information on the neutral start function, refer to "Neutral Start Function".

ReferenceFor more information on the switches for the transmission direction and speed control lever, refer to the Service Manual module Systems Operation, "Input Components" for the machine that is being serviced.

ReferenceFor more information on the key start switch, refer to the Service Manual module Systems Operation, "Input Components" for the machine that is being serviced.

ReferenceFor more information on the power train electronic control module (ECM), refer to the Service Manual module Systems Operation, "Electronic Control Module (Power Train)" for the machine that is being serviced.

Engine Deceleration

Illustration 4	g00877000
(3) Decelerator position sensor (4) Left brake pedal (5) Right brake pedal

Illustration 5	g00877449
(6) Decelerator control

Decelerator position sensor (3) is located in the cab in the left brake pedal assembly. The decelerator position sensor is a pulse width modulated (PWM) sensor. The decelerator position sensor informs the power train ECM of the position of the left brake pedal. When the left brake pedal is depressed, the decelerator position sensor sends a PWM signal to the power train ECM. The power train ECM uses the PWM input in order to decelerate the engine.

Decelerator control (6) is an input of the power train ECM. The input signals to the power train ECM enable the engine deceleration or the input signals disable the engine deceleration. Decelerator control (6) is an on/off switch.

Decelerator position sensor (3) signals the power train ECM to decelerate the engine if decelerator control (6) is enabled. When the decelerator is active, an indicator on the dash will be illuminated. The decelerator position sensor reduces the speed of the engine without downshifting the transmission.

The decelerator is normally used when the throttle lock is enabled. Using the decelerator will not disable the throttle lock. When the left brake pedal is initially depressed, the engine speed will be reduced. The engine speed will increase when the left brake pedal is released. When the left brake pedal is released, the engine speed will automatically increase to the previous speed that was set with the throttle lock.

Note: The left brake pedal will also continue to function as a service brake regardless of the decelerator. The left brake pedal will also neutralize the transmission regardless of the decelerator.

ReferenceFor more information on the decelerator position sensor, refer to the Service Manual module Systems Operation, "Input Components" for the machine that is being serviced.

ReferenceFor more information on the decelerator control, refer to the Service Manual module Systems Operation, "Input Components" for the machine that is being serviced.

ReferenceFor more information on the power train electronic control module (ECM), refer to the Service Manual module Systems Operation, "Electronic Control Module (Power Train)" for the machine that is being serviced.

Transmission Neutralizer Function

Illustration 6	g00877000
(3) Decelerator position sensor (4) Left brake pedal (5) Right brake pedal

Decelerator position sensor (3) is located in the cab in the left brake pedal assembly. The decelerator position sensor is a pulse width modulated (PWM) sensor. The decelerator position sensor informs the power train ECM of the position of the left brake pedal. When the left brake pedal is depressed, the decelerator position sensor sends a PWM signal to the power train ECM. The power train ECM uses the PWM input in order to neutralize the transmission.

The transmission is neutralized by de-energizing the selected direction clutch solenoid. The selected speed clutch solenoid is still energized. The engine rpm will increase when the transmission is neutralized due to the no-load condition from the transmission. This allows full hydraulic power for bucket operation.

Note: When the transmission is neutralized, the speed/direction readout on the Caterpillar Monitoring System changes. The Caterpillar Monitoring System continues to show the speed that is selected but the direction will read neutral.

ReferenceFor more information on the left pedal position sensor, refer to the Service Manual module Systems Operation, "Input Components" for the machine that is being serviced.

ReferenceFor more information on the power train electronic control module (ECM), refer to the Service Manual module Systems Operation, "Electronic Control Module (Power Train)" for the machine that is being serviced.

Parking Brake Function

The parking brake function prevents the operator from operating the machine while the parking brake is engaged. Driving through the parking brake causes accelerated wear to the friction components of the parking brake.

When the parking brake control is disengaged, the transmission will shift normally. When the parking brake control is engaged, the transmission will not shift out of neutral to first speed forward or first speed reverse. If the transmission is in first speed forward or in first speed reverse and the parking brake is moved to the engaged position, the transmission will shift into neutral. All of the modulating valves (transmission clutch) are de-energized. If the transmission is in second speed forward, third speed forward, or fourth speed forward, the transmission will remain engaged.

The parking brake function activates a Warning Category 1 or a Warning Category 3 on the Caterpillar Monitoring System.

Warning Category 1 is activated whenever the parking brake is engaged. The parking brake indicator will flash.

If the operator selects the FORWARD position or the REVERSE position and the parking brake is engaged, the Caterpillar Monitoring System initiates a Warning Category 3. A Warning Category 3 causes the parking brake indicator and the action lamp to flash. The action alarm will also sound.

ReferenceFor more information on the Caterpillar Monitoring System, refer to the Service Manual module Systems Operation, "Monitoring System (Power Train Functions)" for the machine that is being serviced.

ReferenceFor more information on the parking brake pressure switch, refer to the Service Manual module Systems Operation, "Input Components" for the machine that is being serviced.

ReferenceFor more information on the power train electronic control module (ECM), refer to the Service Manual module Systems Operation, "Electronic Control Module (Power Train)" for the machine that is being serviced.

Driving Through the Parking Brake

The power train ECM will allow the operator to drive through the parking brake. The machine should be moved only for a short distance.

In order to drive through the parking brake, the operator must select first speed forward or first speed reverse. The operator must then move the transmission direction control switch to the NEUTRAL position. The operator must then move the transmission direction control switch to the previous direction that was selected.

ReferenceFor more information on the power train electronic control module (ECM), refer to the Service Manual module Systems Operation, "Electronic Control Module (Power Train)" for the machine that is being serviced.

Backup Alarm Function

The backup alarm function alerts surrounding personnel that the machine is backing up. The backup alarm is an output of the power train electronic control module (ECM). The power train ECM activates the backup alarm relay when the transmission direction control switch is in the REVERSE position. The backup alarm relay then activates the backup alarm. The backup alarm receives a +battery signal from the power train ECM when the backup alarm is activated.

The backup alarm has two terminals for electrical connections. One terminal receives power from connector contact J2-37 of the power train ECM. The other contact returns power to connector contact J2-3 and J1-7 of the power train ECM.

ReferenceFor more information on the power train electronic control module (ECM), refer to the Service Manual module Systems Operation, "Electronic Control Module (Power Train)" for the machine that is being serviced.

Diagnostic Operation

The power train electronic control module (ECM) detects faults that occur in most of the input circuits and the output circuits. A fault is detected when the signal at the contact of the power train ECM is outside a valid range. The power train ECM then records the fault. If the fault goes away, the fault information remains stored for future reference.

The diagnostics of the power train ECM are available to assist with the troubleshooting of detected faults. A service code is used to specify each fault. These service codes are shown in the display area of the Caterpillar Monitoring System. Service codes consist of three identifiers: MID, CID and FMI.

Module Identifier (MID) - The MID is a three-digit code that is shown on the display area. The MID is shown for approximately one second before the service code that is shown in the same area. The power train ECM that has diagnosed the fault is logged by the MID. The following examples are of some MID.

Caterpillar Monitoring System ... 030

Power Train ECM ... 081

Note: The MID of the power train control is 081. Make sure that the number 081 precedes the service code of the fault when you are troubleshooting the power train system. The Caterpillar Monitoring System also shows service codes of the faults that are not related to the power train system. MID 081 identifies the power train ECM as the source of the service code.

Component Identifier (CID) - The components that are faulty are noted by the CID. The following components are examples: start relay and reverse solenoid. The CID is a four digit code that is shown on the display area. The CID and the FMI are shown together after the MID has been displayed.

ReferenceFor a list of the CID codes for the power train ECM, refer to the Service Manual module for Testing And Adjusting of this manual.

Failure Mode Identifier (FMI) - The FMI tells the type of failure that has occurred. The following situations are examples: voltage above normal, current below normal and abnormal frequency. The FMI is a two digit code that is shown on the display area. The CID and the FMI are shown together after the MID has been displayed. A decimal point "." precedes the FMI.

ReferenceFor a list of the FMI codes for the power train ECM, refer to the Service Manual module for Testing And Adjusting of this manual.

The power train ECM does not have a display area for displaying diagnostic information to service personnel. Diagnostic information concerning the power train system is sent on the CAT Data Link to the Caterpillar Monitoring System. Service personnel must be familiar with the Caterpillar Monitoring System in order to troubleshoot the power train system.

The service mode of the Caterpillar Monitoring System allows service personnel to see the faults that were detected by the power train ECM. The service mode of the Caterpillar Monitoring System allows service personnel to troubleshoot the faults that were detected by the power train ECM. While the Caterpillar Monitoring System is in the service mode, the service code for any detected fault of the power train electronic control system is shown in the display area of the Caterpillar Monitoring System.

When the service mode is first entered, all service codes for any detected faults scroll in the display area. For troubleshooting and clearing, the particular service code must be placed on hold. The display area continuously alternates between showing the MID, and then showing both the CID and the FMI of the particular service code for the fault that is on hold.

The Caterpillar Monitoring System enters service mode when ground is removed from the service input and the clear input. The mode number 3 for service mode is shown in the display area of the Caterpillar Monitoring System. To place a service code for a fault on hold, ground the service input. To clear a service code for a fault on hold, ground the clear input. The Caterpillar Monitoring System exits service mode when ground is added to the service input and the clear input.

Note: The time that is needed to clear a fault and the time that is needed to set a fault can last less than 1 second up to 60 seconds.

ReferenceFor more information on the CAT Data Link, refer to the Service Manual module Systems Operation, "Data Link" for the machine that is being serviced.

ReferenceFor more information on the power train electronic control module (ECM), refer to the Service Manual module Systems Operation, "Electronic Control Module (Power Train)" for the machine that is being serviced.

ReferenceFor more information on troubleshooting the power train ECM, refer to the Service Manual module Systems Operation, "Electronic Control Module (Power Train)" for the machine that is being serviced.

ReferenceFor more information on troubleshooting the power train electronic control system, refer to the Service Manual module Systems Operation, "Power Train Electronic Control System" for the machine that is being serviced.

ReferenceFor more information on the Caterpillar Monitoring System, refer to the Service Manual module Systems Operation, "Monitoring System (Power Train Functions)" for the machine that is being serviced.

Note: The Service Manual module Systems Operation, Testing and Adjusting, SENR1394, "Caterpillar Monitoring System" should only be used as a reference to the display of the faults of the power train electronic control system. Use the Testing and Adjusting section of this manual in order to troubleshoot the faults of the power train electronic control system.