The throttle lock lamp illuminates in order to indicate that the throttle lock feature is activated. The throttle lock lamp will be illuminated when the engine speed is sustained in either the manual mode or the automatic mode.
The throttle lock lamp receives battery power from the engine control relay. The ECM activates the lamp by providing a path to ground.
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| Illustration 1 | g00827353 |
Schematic | |
Test Step 1. Inspect Electrical Connectors and Wiring
- Thoroughly inspect the J1/P1 ECM connector, the socket for the throttle lock lamp, any other connectors in the circuit, and the associated wiring. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
- Check the harness and wiring for abrasions and for pinch points.
Expected Result:
All connectors, pins and sockets should be completely coupled and/or inserted and the harness and wiring should be free of corrosion, abrasion or pinch points.
Results:
- OK - Proceed to Test Step 2.
- Not OK -
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.
STOP
Test Step 2. Check for Normal Operation of the Lamp
- Activate the throttle lock feature in the automatic mode:
- Turn the keyswitch to the ON position.
- Depress the throttle hold mode switch in the forward direction to the AUTO position.
- Depress the throttle speed set switch in the forward direction to the SET position.
- Monitor the throttle lock lamp.
Note: The lamp should be on.
- Move the throttle hold mode switch to the OFF position.
Note: The lamp should turn off.
Expected Result:
The lamp should turn on when the engine speed is being sustained by the throttle lock feature. The lamp should turn off when the throttle hold mode switch is moved to the OFF position.
Results:
- OK - The throttle lock lamp appears to operating correctly at this time.STOP
- Not OK - The throttle lock lamp remains on. Proceed to Test Step 5.
- Not OK - The throttle lock lamp does not come on. Proceed to Test Step 3.
Test Step 3. Check for Power at the Throttle Lock Lamp
- Turn the keyswitch to the ON position.
- Use a voltage test lamp to check for power between the throttle lock lamp and chassis ground. Check both terminals on the lamp socket.
Note: If the test lamp only lights on one side of the socket, the bulb is bad.
Expected Result:
The test lamp should light.
Results:
- OK - The lamp is receiving power and the bulb is good. Proceed to Test Step 4.
- Not OK - Power On One Side - The lamp is receiving power, but the bulb is bad.
Repair: Replace the bulb.Verify that the repair eliminates the problem.
STOP
- Not OK - No Power - The lamp is not receiving power.
Repair: Repair the power circuit to the lamp. The lamp receives battery power through the engine control breaker. Refer to the Electrical Schematic for more details.Verify that the repair eliminates the problem.
STOP
Test Step 4. Check for Power at the ECM
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| Illustration 2 | g00827352 |
ECM Connector P1 (ECM side) | |
- Disconnect the J1/P1 ECM connector.
- Turn the keyswitch to the ON position.
- Use a voltage test lamp to check for power between P1:28 (Throttle Lock Lamp) and engine ground.
- Turn the keyswitch to the OFF/RESET position.
Expected Result:
The test lamp should light.
Results:
- OK - The circuit from the ECM to the throttle lock lamp appears to be good. Proceed to Test Step 6.
- Not OK - There is an open circuit between the throttle lock lamp and the ECM.
Repair: Repair the open circuit.Verify that the repair eliminates the problem.
STOP
Test Step 5. Check the Harness for a Short to Ground
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| Illustration 3 | g00827352 |
ECM Connector P1 (ECM side) | |
- Disconnect the J1/P1 ECM connector.
- Remove the bulb for the throttle lock lamp from the socket.
- Measure the resistance between P1:28 (Throttle Lock Lamp) and engine ground.
Expected Result:
The resistance should be greater than 20,000 Ohms.
Results:
- OK - The wire is not shorted to ground. Proceed to Test Step 6.
- Not OK - The G946-OR wire is shorted to ground between the ECM and the throttle lock lamp.
Repair: Repair the circuit.Verify that the repair eliminates the problem.
STOP
Test Step 6. Check the ECM
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| Illustration 4 | g00828187 |
ECM connector P1 (wire side) | |
- Ensure that the J1/P1 ECM connector is connected.
- Remove the G946-OR wire from P1:28 (Throttle Lock Lamp).
- Install a voltage test lamp between the +Battery and P1:28 (Throttle Lock Lamp).
- Activate the throttle lock feature in the automatic mode:
- Turn the keyswitch to the ON position.
- Depress the throttle hold mode switch in the forward direction to the AUTO position.
- Depress the throttle speed set switch in the forward direction to the SET position.
- Observe the test lamp.
Note: The test lamp should be on.
- Move the throttle hold mode switch to the OFF position.
Note: The test lamp should turn off.
Expected Result:
The test lamp should illuminate accordingly.
Results:
- OK - The ECM and the circuit appear to be working properly at this time.
Repair: If an intermittent condition is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect" for more details.
STOP
- Not OK - The ECM is not functioning properly.
Repair: Verify your results. Refer to Troubleshooting, "Replacing the ECM" before replacing the ECM.Verify that the repair eliminates the problem.
STOP