3176C, 3406E and 3456 Industrial Engines Troubleshooting – Indicator Lamp – Test

System Operation Description:

Use this procedure to troubleshoot the indicator lamps .

The indicator lamps are located on the display.

The ECM illuminates the lamps for a brief period after the keyswitch is placed in the ON position in order to run diagnostics on the lamp circuits. This also provides a visual check of the lamp’s operation.


Illustration 1 g01434894
Schematic for the engine’s lamp circuits

Test Step 1. Inspect the Electrical Connectors and the Wiring

 

  1. Remove electrical power from the ECM.


Illustration 2 g01139425
ECM
(1) J1/P1 connectors
(2) J2/P2 connectors

  1. Thoroughly inspect the J1/P1 and thoroughly inspect the J2/P2 ECM connectors. Thoroughly inspect any connectors that are associated with the lamp circuits. Refer to Troubleshooting, “Electrical Connectors – Inspect”.


Illustration 3 g01434913
P1 ECM connector

(P1-21) Maintenance overdue lamp

(P1-22) Diagnostic lamp

(P1-27) Warning lamp

  1. Perform a 45 N (10 lb) pull test on each of the wires for the lamp circuits.

 

  1. Check the torque of the allen head screw on the ECM connectors. Refer to Troubleshooting, “Electrical Connectors – Inspect” for the correct torque values.

 

  1. Check the harness and the wiring for abrasion and for pinch points from the display back to the ECM.

Expected Result:

All of the 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 connectors appear to be in good repair. Proceed to Test Step 2. 
  • Not OK – The connectors and/or wiring need repair.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 repair eliminates the problem.

    STOP

Test Step 2. Inspect the Lamp and the Lamp Socket

 

  1. Remove the lamp assembly for the suspect lamp from the display.

 

  1. Measure the resistance of the lamp assembly across the terminals of the lamp socket.

Expected Result:

The measurement across the terminals of the lamp assembly does not indicate an open circuit.

Results:

 

  • OK – The resistance measurement did not indicate an open circuit. The lamp assembly is not the cause of the problem. Proceed to Test Step 3. 
  • Not OK – An open circuit was detected across the terminals of the lamp assembly.Repair: The lamp or the lamp socket is the cause of the problem. If necessary, replace the lamp or the lamp socket. Verify that the repair resolves the original problem.

    STOP

Test Step 3. Check the -Battery Circuit at the Display

 

  1. Ensure that the lamp assembly is removed from the display.

 

  1. At the display, measure the resistance from the -Battery terminal for the lamp to -Battery.

Expected Result:

The measurement does not indicate an open in the -Battery circuit.

Results:

 

  • OK – The measurement does not indicate an open in the -Battery circuit. The circuit between the display and the -Battery is OK. Install the lamp assembly into the lamp socket. Do not install the lamp assembly into the display at this time. Proceed to Test Step 4. 
  • Not OK – The measurement indicates an open in the -Battery circuit.Repair: There is a poor connection between the lamp and -Battery. Repair the wiring and/or the connectors. Replace parts, if necessary. Ensure that all of the connector seals are properly in place and ensure that the connectors are completely coupled. Verify that the repair eliminates the problem.

    STOP

Test Step 4. Check the Harness for an Open Circuit at the ECM Connector

 

  1. Disconnect the J1/P1 connector from the ECM.

 

  1. Measure the resistance between the terminal for the suspect lamp circuit and -Battery .

Expected Result:

An open circuit condition does not exist in the harness.

Results:

 

  • OK – The lamp circuit does not have an open circuit in the harness. Proceed to Test Step 5. 
  • Not OK – At least one of the circuits indicated an open circuit condition.Repair: There is an open circuit in a harness or a connector. Repair the wiring and/or the connectors. Replace parts, if necessary. Ensure that all of the connector seals are properly in place and ensure that the connectors are completely coupled. Verify that the repair eliminates the problem.

    STOP

Test Step 5. Check the Harness for a Short Circuit at the ECM Connector

 

  1. Remove electrical power from the ECM.

 

  1. Remove the lamp from the lamp assembly for the suspect lamp circuit.

 

  1. Disconnect connectors J1/P1 and J2/P2 from the ECM.

 

  1. Measure the resistance between the terminal for the suspect lamp circuit and all of the other terminals on the J1/P1 and the J2/P2 ECM connectors. Be sure to wiggle the wires in the harnesses as you make each resistance measurement.

 

  1. Measure the resistance between the terminal for the suspect lamp circuit and -Battery. Be sure to wiggle the wires in the harnesses as you make each resistance measurement.

 

  1. Install the lamp into the lamp assembly. Restore the display to the original configuration. Connect the J2/P2 ECM connectors.

Expected Result:

Each resistance measurement indicates an open circuit.

Results:

 

  • OK – Each measurement indicates an open circuit. The circuit is OK. Proceed to Test Step 6. 
  • Not OK – A measurement does not indicate an open circuit. There is a short circuit in the harness or in the connectors between the ECM and the suspect lamp.Repair: Repair the wiring and/or the connectors. Replace parts, if necessary. Ensure that all of the connector seals are properly in place and ensure that the connectors are completely coupled. Refer to the electrical schematic for information that relates to the wiring harness. Verify that the repair eliminates the problem.

    STOP

Test Step 6. Check the Operation of the ECM

 

  1. Remove electrical power from the ECM.

 

  1. Disconnect the J1/P1 connector from the ECM.

 

  1. Remove the wire from the terminal for the suspect lamp circuit on the P1 ECM connector.

 

  1. Install a jumper wire into the terminal for the suspect lamp at the P1 ECM connector.

 

  1. Connect the J1/P1 ECM connector..

 

  1. Connect the voltage test lamp between the free end of the jumper wire and -Battery.

 

  1. Restore electrical power to the ECM.

 

  1. Remove electrical power from the ECM.

 

  1. Remove the voltage test lamp and restore the wiring to the original configuration.

Expected Result:

The voltage test lamp momentarily illuminates when electrical power is restored to the ECM.

Results:

 

  • OK – The voltage test lamp illuminates when electrical power is restored to the ECM.Repair: The ECM and the harness appear to be OK but there may be an intermittent problem. Refer to Troubleshooting, “Electrical Connectors – Inspect”.

    STOP

     

  • Not OK – The voltage test lamp does not illuminate when electrical power is restored to the ECM.Repair: The ECM is not powering the lamp circuit correctly. Replace the ECM. Refer to Troubleshooting, “ECM – Replace”.Verify that the problem is resolved.

    STOP

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