Conditions Which Generate This Code:
 | |
| Illustration 1 | g02102213 |
The auto/manual switch has two inputs to the machine electronic control module (ECM). During normal operation, one input is grounded and the other input is open. The valid combinations for each switch position are shown in table 1 that follows. If an invalid combination is detected by the ECM, a circuit failure is present.
| Auto/Manual Switch Status | |||
| Switch Position | 973-BR J1-27 |
977-YL J1-26 |
J878-BR J2-63 |
| AUTO | Open | Ground | Ground |
| Manual | Ground | Open | Ground |
Note: Ensure that the desired diagnostic codes are active.
Note: The following procedure can create additional codes that can be detected by the ECM. Ignore these created diagnostic codes and clear the created diagnostic codes when the problem is corrected.
Possible causes of this diagnostic code are listed:
- There is a failure in the harness.
- The switch has failed.
- There is a short to the battery.
System Response:
The machine response is listed:
- The autoshift is disabled.
Test Step 1. CHECK FOR AN OPEN CIRCUIT.
- Turn the disconnect switch and the key start switch to the OFF position.
- Disconnect the machine harness from the machine ECM.
- At the machine harness connector for the ECM, check the continuity to ground of the open contacts and the grounded contact for each position of the transmission auto/manual switch. Activate and deactivate each position of the auto/manual switch. Refer to table 1 for the correct continuity.
Expected Result:
The continuity check does not agree with the information that is found in table 1.
Results:
- YES - The continuity check does NOT agree with the previous table. The harness or the auto/manual switch has failed. Proceed to Test Step 2.
- NO - The continuity check agrees with the previous table. Proceed to Test Step 3.
Test Step 2. CHECK THE "AUTOSHIFT AUTO/MANUAL" SWITCH.
- Disconnect the machine harness from the auto/manual switch.
- Check the continuity to ground of the open contacts and the grounded contact for each position of the auto/manual switch. Activate and deactivate each position of the auto/manual switch. Refer to table 1 for the correct continuity.
Expected Result:
The continuity check does not agree with table 1.
Results:
- YES - The continuity check does not agree with the previous table. The auto/manual switch has failed.
Repair: Repair the switch or replace the switch.
STOP
- NO - The continuity check agrees with the previous table.
Repair: Repair the machine harness or replace the machine harness.
STOP
Test Step 3. CHECK FOR A SHORT TO THE +BATTERY.
- At the machine harness connector for the ECM, check the continuity from each switch contact to all possible sources of positive battery.
Expected Result:
Continuity exists between one of the sources of the battery voltage and the switch circuit.
Results:
- YES - Continuity exists between one of the sources of battery voltage. The machine harness has failed.
Repair: Repair the machine harness or replace the machine harness.
STOP
- NO - Continuity does not exist between one of the sources of battery voltage and the switch circuit. The machine harness is correct. It is unlikely that the ECM has failed. Exit this procedure and perform the diagnostic code procedure again.
Repair: If the cause is not found, replace the ECM. Refer to Troubleshooting, "Electronic Control Module (ECM) - Replace" for more information on replacing the ECM.
STOP