5031448 JOHNSON LEVER, CLUTCH CONTROL

Illustration 1 g01174890
Schematic for the engine pressure sensors
Test Step 1. Inspect the Electrical Connectors and the Wiring
Turn the keyswitch to the OFF position.
Illustration 2 g01174896
Sensor locations
(1) Fuel pressure sensor
(2) Turbocharger outlet pressure sensor
(3) Atmospheric pressure sensor
(4) Engine oil pressure sensor
(5) J2/P2 ECM connector
Thoroughly inspect the connectors that are for pressure sensors (1), (2), (3), and (4). Also, thoroughly inspect ECM connector (5). Refer to Troubleshooting, "Electrical Connectors - Inspect".
Illustration 3 g01174894
Terminal locations at the P2 ECM connector that are for the engine pressure sensors
(P2-2) +5 V sensor supply
(P2-3) Sensor return
(P2-14) Atmospheric pressure
(P2-16) Fuel pressure
(P2-24) Engine oil pressure
(P2-40) Turbocharger outlet pressure
Illustration 4 g01159881
Terminal locations at the sensor connector that are for the engine pressure sensors
(Terminal A) +5 V sensor supply
(Terminal B) Sensor return
(Terminal C) Signal
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connectors that are associated with the circuit.
Check the allen head screw for each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and wiring for abrasion and for pinch points from the pressure sensors back to the ECM. Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted. 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 - There is a problem in the connectors and/or wiring.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.Verify that the repair eliminates the problem.STOPTest Step 2. Check the Supply Voltage at the Sensor Connector
Turn the keyswitch to the OFF position.
Disconnect the harness connectors for the following sensors:
Turbocharger outlet pressure sensor
Engine oil pressure sensor
Fuel pressure sensor
Atmospheric pressure sensor
Turn the keyswitch to the ON position. Note: Be sure to wiggle the harness during the following measurements in order to reveal an intermittent condition.
Measure the voltage between terminals A and B at each sensor connector on the engine harness.
Turn the keyswitch to the OFF position.
Connect 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. The voltage is correct at the sensor connectors. Proceed to Test Step 3.
Not OK - At least one voltage measurement is not 5.0 0.2 VDC.Repair: There is a problem with the supply circuit for the pressure sensors. Refer to Troubleshooting, "5 Volt Engine Pressure Sensor Supply Circuit - Test".STOPTest Step 3. Check for Active Diagnostic Codes
Connect Caterpillar Electronic Technician (ET) to the service tool connector.
Turn the keyswitch to the ON position.
Observe the "Active Diagnostic" screen on Cat ET. Wait at least 15 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 an -03 diagnostic code or an -04 diagnostic code. Expected Result:No diagnostic codes are active.Results:
OK - No diagnostic codes are active for the engine pressure sensors.Repair: The problem may have been related to a faulty connection in the harness. Carefully reinspect the connectors and wiring. Refer to Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - A -04 diagnostic code is active at this time. Proceed to Test Step 4.
Not OK - A -03 diagnostic code is active at this time. Proceed to Test Step 5.Test Step 4. Disconnect the Suspect Sensor and Check for an Open Circuit
Turn the keyswitch to the OFF position.
Disconnect the sensor connector of the suspect sensor with the active -04 diagnostic code.
Turn the keyswitch to the ON position. Wait at least 15 seconds for activation of the diagnostic codes.
Access the "Active Diagnostic Code" screen on Cat ET. Check for an active -03 diagnostic code.
Turn the keyswitch to the OFF position. Expected Result:An -03 diagnostic code is now active for the disconnected sensor.Results:
OK - An -04 diagnostic code was active before you disconnected the sensor. An -03 diagnostic code became active after the sensor was disconnected.Repair: Temporarily connect a new sensor to the harness, but do not install the new sensor in the engine. Verify that there are no active diagnostic codes for the sensor. If there are no active diagnostic codes for the sensor, permanently install the new sensor. Clear any logged diagnostic codes.STOP
Not OK - A -04 diagnostic code is still active for the suspect sensor. There is a short circuit between the sensor harness connector and the ECM. Leave the sensor disconnected. Proceed to Test Step 8.Test Step 5. Check the Pull-up Voltage at the Sensor Connector
Turn the keyswitch to the ON position.
Disconnect the suspect sensor.
Measure the voltage between terminal C (signal) and terminal B (sensor return) at the sensor connector.
Turn the keyswitch to the OFF position. Expected Result:The voltage is greater than 5.5 VDC.Results:
OK -