TRANSMISSION CONTROL VALVE GROUP 4M7968 - Caterpillar

Illustration 5 g01194115
Left side engine view (typical example) (1) Injection actuation pressure sensor (2) Atmospheric pressure sensor (3) Turbocharger outlet pressure sensor (4) Fuel pressure sensor (5) Engine oil pressure sensorTest Step 1. Inspect the Electrical Connectors and the Wiring
Remove electrical power from the ECM.
Thoroughly inspect ECM connectors J1/P1 and J2/P2. Also inspect the connectors for pressure sensors. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector and the sensor connectors that are associated with the active diagnostic code.
Check the torque of the allen head screw on the ECM connectors. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and wiring for abrasions and for pinch points from the sensors back to the ECM.Expected Result:All connectors, pins and sockets are completely coupled and/or inserted and the harness and wiring are free of corrosion, of abrasion and of pinch points.Results:
OK - The harness and wiring are OK. Proceed to Test Step 2.
Not OK - Repair: Repair the wiring and/or the connectors. Replace parts, if necessary. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.Verify that the problem is resolved.STOPTest Step 2. Check the Voltage on the +5 V Supply Wire
Disconnect the harness connectors for the following sensors:
Fuel pressure sensor
Engine oil pressure sensor
Injection actuation pressure sensor
Turbocharger outlet pressure sensor
Atmospheric pressure sensor
Turbocharger Inlet pressure sensor
Restore electrical power to the ECM.
Measure the voltage between terminals A (supply) and B (return) at each sensor connector on the engine harness.Note: Be sure to wiggle the harness during the following measurements in order to reveal an intermittent condition.
Remove electrical power from the ECM.
Reconnect all of the sensors.Expected Result:Each voltage measurement is 5.0 0.2 VDC.Results:
OK - Each voltage measurement is 5.0 0.2 VDC. Proceed to Test Step 3.
Not OK - At least one voltage measurement is not 5.0 0.2 VDC.Repair: Refer to Troubleshooting, "Analog Sensor Supply Circuit - Test".STOPTest Step 3. Check for Active Diagnostic Codes
Connect the Caterpillar Electronic Technician (ET) to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools".
Restore electrical power to the ECM.
Use Cat ET to check for active diagnostic codes. Wait at least 30 seconds so that any codes may become active. Look for an active diagnostic code for an engine pressure sensor.
Determine if the problem is related to a 03 diagnostic code or to a 04 diagnostic code.Expected Result:No diagnostic codes are active.Results:
OK - No diagnostic codes are active for the engine pressure sensors.Repair: If any of the above codes are logged and the engine is not running properly, refer to Troubleshooting, "Troubleshooting Without a Diagnostic Code".If the engine is running properly at this time, there may be an intermittent problem in a harness that is causing the codes to be logged. Refer to Troubleshooting, "Electrical Connectors - Inspect".STOP
Active 04 Code - A 04