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| Illustration 1 | g01447474 |
Connections of the parking brake switch | |
This diagnostic code is associated with the parking brake switch. The switch is connected to two inputs of the ECM. The inputs are "Normally Open" and "Normally Closed". One of the inputs is open and the other input is grounded during proper operation.
The possible causes of this diagnostic code are listed:
- The normally open contact and the normally closed contact are grounded.
- The contact that is currently open is shorted to ground.
Before performing this procedure, inspect the harness connectors that are involved in the circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all of the connections in the circuit are clean and secure. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure.
Note: The following test procedure may create other diagnostic codes. Clear the diagnostic codes when the problem has been corrected. Verify that the CID 0070 FMI 04 is active before performing this procedure.
Use a digital multimeter for the measurements in this procedure.
| Status of the Switch | |||
|---|---|---|---|
| MODE | Switch Position | J2-53 wire 419-yl |
J2-52 wire G764-pk |
| Brake OFF | Up | Open | Closed |
| Brake ON | Down | Closed | Open |
System Response:
A level 2 warning is generated. The ECM retains the last known good state until the switch is required. Once the parking brake is required, the machine is locked out until the diagnostic code is cleared.
Test Step 1. CHECK THE SWITCH
- Check for continuity between the "Normally Closed" contact and the "Common" contact of the switch.
- Press the switch. Release the switch and check for continuity.
- Check for continuity between the "Common" contact and the "Normally Closed" contact of the switch.
- Press the switch. Release the switch and check for continuity.
Expected Result:
The continuity check agrees with Table 1.
Results:
- OK - The continuity check agrees. Proceed to Test Step 2.
- NOT OK - The continuity check does not agree. The switch has failed.
Repair: Replace the switch. Verify that the new switch corrects the diagnostic code.
STOP
Test Step 2. CHECK THE SIGNAL CIRCUITS FOR A SHORT TO GROUND
- Reconnect the switch to the machine harness.
- The machine harness connectors remain disconnected from the ECM.
- At the machine harness connector for the ECM, check for continuity between contact J2-52 (wire G764-PK) and frame ground.
- Press the switch. Release the switch and check for continuity.
- At the machine harness connector for the ECM, check for continuity between contact J2-53 (wire 419-YL) and frame ground.
- Press the switch. Release the switch and check for continuity.
Expected Result:
The continuity check agrees with Table 1.
Results:
- OK - The continuity check agrees.
Repair: If the cause of the problem is not found, contact your dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the ECM requires replacement, see Troubleshooting, "Electronic Control Module (ECM) - Replace".
STOP
- NOT OK - The continuity check does not agree. There is a short in the machine harness.
Repair: Repair the machine harness or replace the machine harness.
STOP