C-10, C-12, C-15 and C-16 Industrial Engines – Diagnostic Lamp Circuit – Test

System Operation Description:

The diagnostic lamp is used to inform the operator of diagnostic codes or event codes that are active.

Illustration 1	g01080816
Schematic for the diagnostic lamp

The Electronic Control Module (ECM) provides a path to ground for the diagnostic lamp. When the ECM connects the diagnostic lamp to ground the diagnostic lamp will turn on.

Illustration 2	g00741104
Terminal locations for the customer connector

Test Step 1. Check for Normal Operation of the Diagnostic Lamp

1. Place the engine control in the ON mode while you monitor the diagnostic lamp.

Expected Result:

The diagnostic lamp turns on for five seconds. Then, the diagnostic lamp turns off. If a diagnostic code is active, the diagnostic lamp will flash.

Results:

• Yes – The diagnostic lamp appears to be operating correctly at this time.STOP

• No – The diagnostic lamp is not operating correctly. Proceed to Test Step 2.

Test Step 2. Inspect Electrical Connectors and Wiring

1. Place the engine control in the OFF/RESET mode and thoroughly inspect the J61/P61 customer connector, and J1/P1 ECM connector. Refer to Troubleshooting, “Electrical Connectors – Inspect” for details.

2. Perform a 45 N (10 lb) pull test on each of the wires in the circuit that is associated with the diagnostic lamp.

   Refer to Illustration 1.

3. Check the J61/P61 customer connector (allen head screw) for the proper torque. Refer to Troubleshooting, “Electrical Connectors – Inspect” for details.

4. Check the ECM connector J1/P1 (allen head screw) for the proper torque. Refer to Troubleshooting, “Electrical Connectors – Inspect” for details.

5. 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 and of pinch points.

Results:

• OK – The connectors and wiring are OK. Proceed to Test Step 3.

• Not OK – There is a problem with the connectors and/or with the 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 3. Test the Diagnostic Lamp Circuit at the ECM Connector

Illustration 3	g00806996
Terminal locations for the diagnostic lamp

1. Disconnect ECM connector J1/P1.

2. Remove wire F404-RD from ECM connector P1-28.

3. Connect a wire jumper between wire F404-RD and engine ground.

4. Place the engine control in the ON mode and observe the diagnostic lamp.

Expected Result:

The diagnostic lamp turns on while the jumper is connected to wire F404-RD. Also, the diagnostic lamp turns off when the jumper is removed from wire F404-RD.

Results:

• OK – The circuit for the diagnostic lamp is functioning properly. Proceed to Test Step 6.

• Not OK – The diagnostic lamp did not turn on. The diagnostic lamp circuit is not functioning properly. Proceed to Test Step 4.

Test Step 4. Test the Diagnostic Lamp Circuit at the Diagnostic Lamp

1. Remove wire F404-RD from the diagnostic lamp.

2. Connect a wire jumper between the diagnostic lamp and engine ground.

3. Place the engine control in the ON mode and observe the diagnostic lamp.

Expected Result:

The diagnostic lamp turns on while the jumper is connected. Also, the diagnostic lamp turns off when the jumper is removed.

Results:

• OK – The circuit for the diagnostic lamp is functioning properly.

  Repair: Repair the wire F404-RD between the diagnostic lamp and the ECM connector P1-28.

  STOP

• Not OK – The diagnostic lamp did not turn on. The diagnostic lamp circuit is not functioning properly. Proceed to Test Step 5.

Test Step 5. Check the Voltage from the Keyswitch to the Diagnostic Lamp

1. Place the engine control in the OFF/RESET mode.

2. Remove the wire from the terminal R of the keyswitch.

3. Place the engine control in the ON mode.

4. Measure the voltage on terminal B of the keyswitch to engine ground.

5. Measure the voltage on terminal R of the keyswitch to engine ground.

6. Place the engine control in the OFF/RESET mode.

Expected Result:

Voltage is present on terminal B and terminal R at the keyswitch.

Results:

• OK – Voltage is present on terminal B and terminal R at the keyswitch.

  Repair: If voltage is present on terminal R, repair the wire between the keyswitch and the diagnostic lamp. Verify that the breaker is not tripped. Return all wiring to the original configuration. Verify that the problem is eliminated.

  STOP

• Not OK – Voltage is not present on terminal B at the keyswitch.

  Repair: If voltage is not present on terminal B, repair the wire between the +Battery and the keyswitch. Verify that the breaker is not tripped. Check the battery’s no-load voltage. Return all wiring to the original configuration. Verify that the problem is eliminated.

  STOP

• Not OK – Voltage is not present on terminal R at the keyswitch.

  Repair: If voltage is present on terminal B of the keyswitch but not present on terminal R, replace the keyswitch. Return all wiring to the original configuration. Verify that the problem is eliminated.

  STOP

Test Step 6. Check ECM Operation of the Diagnostic Lamp.

1. Fabricate a jumper wire 100 mm (4 inch) long. Crimp a Deutsch pin to both ends of the wire.

2. Insert the jumper into P1-28.

3. Reconnect ECM Connector J1/P1.

4. Connect one probe of a voltage test lamp to the wire jumper in P1-28.

5. Connect the other probe of the voltage test lamp to +Battery.

6. Place the engine control in the ON mode.

Expected Result:

The test lamp turns ON for five seconds. Then, the test lamp turns OFF.

Results:

• OK – The ECM is operating correctly. The circuit appears to be operating correctly.

  Repair: The problem may be intermittent. If the problem is intermittent, refer to the diagnostic functional test Troubleshooting, “Electrical Connectors – Inspect”.

  STOP

• Not OK – The ECM is not operating correctly. Temporarily connect a test ECM. Check the operation of the diagnostic 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