3406E, C12, C15 and C18 Marine Engines Caterpillar

Use this procedure to troubleshoot any suspect problems with the following indicator lamps:

• Low oil pressure lamp

• High coolant temperature lamp

• Engine coolant level indicator lamp

• Maintenance indicator lamp

• Diagnostic lamp

• Warning lamp

The indicator lamps are activated by the Electronic Control Module (ECM) in order to inform the operator of various engine events.

The most likely cause of a problem with an indicator lamp is the bulb. The next most likely cause is a problem with a wire or with a connector. The least cause is a problem with the ECM.

Illustration 1	g01150575
Schematic for the indicator lamps

Test Step 1. Inspect the Electrical Connectors and the Wiring

1. Remove the electrical power from the ECM.

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Illustration 2	g01146374
Engine view (typical example) (1) J1/P1 ECM connector

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Illustration 3	g01146383
Engine view (typical example) (2) J61/P61 customer connectors

2. Thoroughly inspect connectors (1) and (2). Refer to diagnostic functional tests Troubleshooting, "Electrical Connectors - Inspect" for details.

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Illustration 4	g01130328
P1 terminals that are associated with the indicator lamps (P1-19) Diagnostic lamp (P1-20) Warning lamp (P1-21) Maintenance indicator lamp (P1-28) Low oil pressure lamp (P1-29) High coolant temperature lamp (P1-30) Engine coolant level indicator lamp (P1-53) +Battery (P1-63) −Battery (P1-70) Keyswitch

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Illustration 5	g01150664
J61/P61 terminals that are associated with the indicator lamps (3) −Battery (8) +Battery (20) Engine coolant level indicator lamp (21) High coolant temperature lamp (22) Maintenance indicator lamp (23) Low oil pressure lamp (24) Diagnostic lamp (25) Warning lamp (30) Keyswitch

3. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the indicator lamps.

4. Check the allen head screw on each ECM connector for the proper torque. Refer to diagnostic functional tests Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.

5. Check the allen head screw on the customer connector for the proper torque. Refer to diagnostic functional tests Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.

6. Check the harness and wiring for abrasions and for pinch points from the indicator lamps 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 connectors 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.

  STOP

Test Step 2. Check for Normal Operation of the Lamp

1. Restore the electrical power to the ECM and monitor the indicator lamps.

Expected Result:

The indicator lamps illuminate for five seconds. Then, the indicator lamps do not illuminate.

Results:

• OK - The indicator lamps illuminate for five seconds. Then, the indicator lamps do not illuminate.

  Repair: The problem appears to be resolved. The original problem was probably caused by a poor electrical connection. If an intermittent problem is suspected, refer to diagnostic functional tests Troubleshooting, "Electrical Connectors - Inspect".

  STOP

• Not OK - An indicator lamp does not illuminate. Proceed to Test Step 3.

Test Step 3. Measure the Voltage at the Lamp Socket

1. Use a test lamp to check for voltage at the suspect lamp socket within the first five seconds after the electrical power is restored to the ECM.

Expected Result:

The test lamp should illuminate during the first five seconds after the electrical power is restored to the ECM.

Results:

• OK - The test lamp illuminates during the first five seconds after the electrical power is restored to the ECM.

  Repair: Replace the bulb.Verify that the repair eliminates the problem.

  STOP

• Not OK - The test lamp did not illuminate during the first five seconds after the electrical power was restored to the ECM. Proceed to Test Step 4.

Test Step 4. Bypass the ECM in order to Test the Lamp Circuit

1. Fabricate a jumper wire that can be used to connect two terminals at the P1 ECM connector. Crimp connector pins to both ends of the wire.

2. Disconnect the J1/P1 connectors.

3. Use the jumper wire to short one leg of the indicator lamp to the appropriate circuit connection. Refer to Table 1 for the appropriate terminals.
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   Table 1

   P1 Terminals for the Connection of the Jumper Wire
   Indicator Lamp	Terminals
   Low coolant level	P1-30	P1-63
   Low oil pressure	P1-28	P1-63
   High coolant temperature	P1-29	P1-63
   Maintenance indicator	P1-21	P1-70
   Diagnostic lamp	P1-19	P1-70
   Warning lamp	P1-20	P1-70

4. Restore the electrical power to the ECM and observe the indicator lamp.

5. Remove the jumper wire and observe the indicator lamp.

Expected Result:

The indicator lamp illuminates while the jumper wire is connected to both terminals. The indicator lamp does not illuminate when the jumper wire is removed.

Results:

• OK - The indicator lamp illuminates while the jumper wire is connected to both terminals. The indicator lamp does not illuminate when the jumper wire is removed. The circuit for the indicator lamp is functioning properly.

  Repair: Perform the following procedure:

  1. Connect the J1/P1 connectors.

  2. Restore the electrical power to the ECM and monitor the indicator lamps.

     The indicator lamps should illuminate for five seconds. Then, the indicator lamps should not illuminate.

     If the indicator lamps illuminate for five seconds, the problem is resolved. Return the engine to service.

     STOP.

  3. If the indicator lamps do not illuminate for five seconds, there may be a problem with the ECM. It is unlikely that the ECM has failed. Exit this procedure and perform this entire procedure again.

     If the problem is not resolved, temporarily connect a test ECM. Check the operation of the indicator lamps 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. Refer to electronic troubleshooting Troubleshooting, "Replacing the ECM".

  STOP

• Not OK - The indicator lamp does not illuminate while the jumper wire is connected to both terminals. There is a problem in the wiring for the indicator lamp. There may be a problem in a connector.

  Repair: Repair the lamp circuit. Verify that the repair eliminates the problem.

  STOP