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| Illustration 1 | g01460738 |
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Connections of the lockup clutch switch | |
The ECM detects most failures with the lockup clutch function. However, the ECM does NOT detect failures with the lockup clutch switch.
The possible causes of the failure are listed below:
- The signal circuit (wire G765-GN(Green)) is open.
- The signal circuit (wire G765-GN(Green)) is shorted to ground.
- The signal circuit (wire G765-GN(Green)) is shorted to the + battery.
- The switch has failed.
- The ECM has failed. This is unlikely.
If the lockup clutch function does not operate correctly, check for related diagnostic codes. Correct any related diagnostic codes. The following is a list of related diagnostic codes:
- CID 0041 Supply for +8 Volt
- CID 0669 Torque Converter Output Speed Sensor
- CID 0678 Impeller Clutch Solenoid Valve
- CID 0679 Lockup Clutch Solenoid Valve
- CID 1712 Torque Converter Pedal Position Sensor
Note: 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: Use a digital multimeter for the measurements in this procedure.
Test Step 1. CHECK THE OPERATION OF THE SWITCH
- Place the disconnect switch and the key start switch in the OFF position.
- Disconnect the switch from the machine harness.
- Place the leads of the multimeter on contact 2 and contact 3.
- Toggle the switch and note the resistance value.
Expected Result:
The resistance alternates between 5 ohms and 5000 ohms.
Results:
- OK - The resistance alternates between 5 ohms and 5000 ohms. The switch is operating correctly. Proceed to Test Step 2.
- NOT OK - The resistance value does NOT alternate between 5 ohms and 5000 ohms as the switch is toggled. The switch has failed.
Repair: Replace the switch.
STOP
Test Step 2. CHECK THE SIGNAL CIRCUIT FOR AN OPEN IN THE HARNESS
- The switch remains disconnected from the machine harness connector.
- Disconnect the machine harness connectors from the ECM.
- Measure the resistance between contact J1-35 (wire G765-GN(Green)) and contact 3 (wire G765-GN(Green)) at the switch.
Expected Result:
The resistances should be less than 5 ohms.
Results:
- OK - The resistances are less than 5 ohms. Proceed to Test Step 3.
- NOT OK - The resistance is greater than 5000 ohms. There is an open in the machine harness.
Repair: Repair the machine harness or replace the machine harness.
STOP
Test Step 3. CHECK THE SIGNAL CIRCUITS FOR A SHORT TO GROUND
- Turn the key start switch to the OFF position.
- The switch remains disconnected from the harness connector.
- The machine harness connectors remain disconnected from the ECM.
- Measure the resistance between contact J1-35 (wire G765-GN(Green)) and all connector contacts that are used in the machine harness connector for the ECM.
Expected Result:
The resistances should be greater than 5000 ohms for each measurement.
Results:
- OK - Each resistance measurement is greater than 5000 ohms. Proceed to Test Step 4.
- NOT OK - The resistance is less than 5000 ohms on one of the readings.
Repair: The circuit with the low resistance is shorted in the machine harness. Repair the machine harness or replace the machine harness.
STOP
Test Step 4. CHECK THE SIGNAL CIRCUITS FOR A SHORT TO THE + BATTERY
- Measure the resistance between contact J1-325 (wire G765-GN(Green)) and all connector contacts that are used in the machine harness connector for the ECM.
Expected Result:
The resistances should be greater than 5000 ohms.
Results:
- OK - The resistances are greater than 5000 ohms.
Repair: It is unlikely that the ECM has failed. Exit this procedure and perform this procedure again. If the diagnostic code is still present, replace the ECM. Refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace".
STOP
- NOT OK - The resistance is less than 5000 ohms on at least one of the readings.
Repair: The circuit with the low resistance is shorted in the machine harness. Repair the machine harness or replace the machine harness.
STOP