797B Off-Highway Truck. Indicator Lamp for Body Up Does Not Illuminate During the Power Up Self Test

System Operation Description:

Schematic Of The Body Up Indicator Lamp

Test Step 1. CHECK THE INDICATOR LAMP.

1. Turn the key start switch and the disconnect switch to the OFF position.

2. Replace the indicator lamp with a similar indicator lamp that is known to be correct.

3. Turn the disconnect switch and the key start switch to the ON position.

4. Observe the indicator lamp.

Expected Result:

The indicator lamp functions properly.

Results:

• OK - The indicator lamp functions properly during the three second test cycle. The original lamp has failed.Repair: Replace the indicator lamp.
  Stop.
• NOT OK - The indicator lamp is not the problem. Proceed to Test Step 2.

Test Step 2. CHECK THE HARNESS.

1. Turn the key start switch and the disconnect switch to the OFF position.

2. Disconnect the machine harness from the ECM.

3. Turn the disconnect switch and the key start switch to the ON position.

4. At the machine harness connector for the chassis ECM, measure the voltage between connector J2-1 wire (173-J158-RD) and frame ground. The voltage must be above 20.5 DCV in order to illuminate the indicator lamp.

5. Turn the key start switch and the disconnect switch to the OFF position.

6. Install a jumper wire from connector J2-1 wire (173-J158-RD) to connector J2-40 wire (H430-J425-BU).

7. At the machine harness connector for the chassis ECM, connect J2-59 wire (H863-J432-BU) to frame ground.

8. Turn the disconnect switch and the key start switch to the ON position.

Expected Result:

The indicator lamp illuminates.

Results:

• OK - The indicator lamp illuminates. The harness circuit is functioning correctly. The ECM may have failed.Repair: It is unlikely that the ECM has failed. Exit this procedure and perform this troubleshooting procedure again. Replace the ECM if the cause of the problem is not found. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace".
  Stop.
• NOT OK - The indicator does NOT illuminate. There is an open in the harness. Proceed to Test Step 3.

Test Step 3. CHECK THE HARNESS.

1. Remove wire (H430-K21-BU) from the socket of the indicator lamp.

2. Check for an open circuit between the following points. Check between the circuit of the indicator lamp (wire H430-K21-BU) and J2-40.

3. Check for an open circuit between the following points. Check between the circuit of the indicator lamp (wire H863-K46-BU) and contact J2-59.

Expected Result:

The circuits are correct.

Results:

• OK - The circuits are correct. Stop.
• NOT OK - The circuits are NOT correct.Repair: Repair the harness or replace the harness.
  Stop.

Indicator Lamp for Body Up Is On Continuously

System Operation Description:

Schematic Of The Body Up Indicator Lamp

Test Step 1. CHECK THE HARNESS.

1. Turn the key start switch and the disconnect switch to the OFF position.

2. Disconnect the machine harness from the ECM.

3. At the ECM connector, install a jumper wire from contact J2-59 to frame ground.

4. Turn the disconnect switch to the ON position.

5. Observe the indicator lamp.

6. Turn the key start switch to the ON position.

7. Observe the indicator lamp.

Expected Result:

The indicator lamp is ON.

Results:

• OK - The indicator lamp is ON. There is a short in the harness.Repair: The harness circuit (wire H430-J425-BU) is shorted to the +battery. Repair the harness or replace the harness.
  Stop.
• NOT OK - The indicator lamp is NOT ON. The harness circuit is correct. Reconnect all harness connectors and recheck the system. The ECM may have failed.Repair: It is unlikely that the ECM has failed. Ensure that replacement of the ECM is necessary. If the cause of the problem is not found replace the ECM. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace".
  Stop.

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797B Off-Highway Truck. Indicator Lamp for Body Up Does Not Illuminate During the Power Up Self Test 2012-12-25T18:24:00-08:00 Rating: 4.5 Diposkan Oleh: Unknown