P0688
P0688-AUTO SHUTDOWN SENSE CIRCUIT LOW
For a complete wiring diagram refer to Diagrams/Electrical.
- When Monitored:
With ignition key on. Battery voltage greater than 10 volts.
- Set Condition:
No voltage sensed at the PCM when the ASD is energized or voltage is sensed when the ASD is not energized. One Trip Fault. Three good trips to turn off the MIL.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.
Diagnostic Test
1. VERIFY ASD DTC
NOTE: Diagnose P0685 - Auto Shutdown Control Circuit first if it set along with this DTC.
Turn the ignition on.
With a scan tool, select View DTCs.
Is the DTC currently Active?
Yes
- Go To 2
No
- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
2. EXCESSIVE RESISTANCE IN THE (F342) ASD CONTROL OUTPUT CIRCUIT
Turn the ignition off.
Disconnect the C1 PCM harness connector.
Disconnect the C5 TIPM harness connector.
CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.
Measure the resistance of the (F342) ASD Control Output circuit from the C5 TIPM harness connector to the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?
Yes
- Go To 3
No
- Repair the excessive resistance in the (F342) ASD Control Output circuit. Inspect the related in-line connectors and splices.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
3. EXCESSIVE RESISTANCE IN THE (F342) ASD CONTROL OUTPUT CIRCUIT
Disconnect the C3 PCM harness connector.
Measure the resistance of the (F342) ASD Control Output circuit from the C5 TIPM harness connector to the appropriate terminals of special tool #8815.
Is the resistance below 5.0 ohms at each terminal?
Yes
- Go To 6
No
- Repair the open in the (F342) ASD Control Output circuits.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
4. (F342) ASD CONTROL OUTPUT CIRCUIT SHORTED TO GROUND
Measure the resistance between ground and the (F342) ASD Control Output circuit at the C5 TIPM harness connector.
Is the resistance below 100 ohms?
Yes
- Repair the short to ground in the (F342) ASD Control Output circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No
- Go To 5
5. (F342) ASD CONTROL OUTPUT CIRCUIT SHORTED TO VOLTAGE
Ignition on, engine not running.
Using a voltmeter measure the voltage on the (F342) ASD Control Output circuit in the C5 TIPM harness connector.
Is the voltage above 0 volts?
Yes
- Repair the short to voltage in the (F342) ASD Control Output circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No
- Go To 6
6. TIPM
Turn the ignition off.
Connect the C1 and C3 PCM harness connectors and the C5 TIPM harness connector.
Ignition on, engine not running.
Using the scan tool in the PCM, actuate the ASD.
With a 12-volt test light connected to ground, probe the (K51) ASD Control circuit at the C2 TIPM terminal connection.
Does the test light illuminate brightly and flash on an off during the actuation?
Yes
-
NOTE: Before continuing, check the TIPM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.
If OK, replace the TIPM.
No
- Go To 7
7. PCM
NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.
Were there any problems found?
Yes
- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No
- Replace and program the Powertrain Control Module.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test