8M0021912 Mariner GROMMET

Illustration 1 g01021530
Schematic for low oil pressure lamp
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P1 ECM connector (P1-28) Low engine oil pressure lampTest Step 1. Inspect Electrical Connectors And Wiring
Thoroughly inspect the J1/P1 ECM connector and the wiring that is associated with the low engine oil pressure lamp. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on P1-28 (low engine oil pressure lamp).
Check the allen head screw on each ECM connector and the customer connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and wiring for abrasions and for pinch points from the battery 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 or of pinch points.Results:
OK - Proceed to Test Step 2.
Not OK - 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.STOPTest Step 2. Check the Wiring from the ECM to the Machine Control Module
Turn the keyswitch to the OFF position.
Disconnect the connector J1/P1 for the machine harness.
Check the wiring from P1-28 to terminal 41 of the machine control module. Use a multimeter to check for shorts to ground and for open circuits.Expected Result:The wiring from P1-28 to terminal 41 of the machine control module does not have any open circuits or short circuits.Results:
OK - The wiring for the circuit of the engine oil pressure lamp is OK. Proceed to Test Step 3.
Not OK - There is a problem in the machine wiring. Repair the machine wiring, as required.STOPTest Step 3. Check For Normal Operation Of The Lamp
Monitor the low engine oil pressure lamp.
Turn the keyswitch to the ON position. The lamp should turn on for five seconds. Then, the lamp should turn off.
The lamp will remain on if there is an active diagnostic code. If there is an active diagnostic code, connect the Caterpillar Electronic Technician (ET) in order to read the active diagnostic code. Troubleshoot the problem.Expected Result:The low engine oil pressure lamp turns on and the low engine oil pressure lamp turns off per the above description.Results:
OK - The circuit for the low engine oil pressure lamp appears to operating correctly at this time.STOP
Not OK - Proceed to Test Step 4.Test Step 4. Check the Output at the ECM
Turn the keyswitch to the OFF position.
Use a Deutsch removal tool to remove the wire from P1-28 (low engine oil pressure lamp).
Connect the probe of a multimeter to terminal 28 (low engine oil pressure lamp) and connect the other probe to engine ground. Set the multimeter to read resistance.
Start the engine.
The multimeter should indicate high resistance (open) for the first five seconds after the engine has started. The multimeter will then read less than 10 Ohms (short) after the oil pressure reaches operating pressure.Expected Result:The engine oil pressure is high during the first five seconds of engine operation and then low after the oil pressure reaches operating pressure.Results:
OK - The ECM is operating correctly. There is a problem in the machine wiring or in the monitor. Repair the machine wiring or the monitor, as required.STOP
Not OK - Temporarily connect a test ECM. Check the operation of the engine oil pressure lamp when the test ECM is installed. If the problem is resolved with the test ECM, then reconnect the suspect ECM. If the problem returns with the suspect ECM, then replace the ECM.STOP