P0688

P0688-AUTO SHUTDOWN RELAY SENSE CIRCUIT LOW





For a complete wiring diagram, refer to the Wiring Information.

- When Monitored:
With ignition key on. Battery voltage greater than 10 Volts.

- Set Condition:
No voltage sensed at the Powertrain Control Module (PCM) when the ASD relay is energized. One Trip Fault. Three good trips to turn off the MIL.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. ACTIVE DTC

NOTE: If any of the following component DTCs have set along with P0688, diagnose them first before continuing: Ignition Coil(s), Fuel Injector(s) , ASD Control.

1. Ignition on, engine not running.
2. With the scan tool, select View DTCs.

Is the DTC Active at this time?

Yes

- Go To 2

No

- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test

2. (K51) ASD CONTROL CIRCUIT OPEN
1. Turn the ignition off.
2. Measure the resistance of the (K51) ASD Control circuit from the PDC harness connector to the appropriate terminal of PCM harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 4

No

- Repair the open in the (K51) ASD Control circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

3. (F342) ASD CONTROL OUTPUT CIRCUIT(S) SHORTED TO GROUND
1. Measure the resistance between ground and each of the (F342) ASD Control Output circuits in the PDC harness.

Is the resistance below 100 Ohms?

Yes

- Repair the short to ground in the (F342) ASD Control Output circuit(s).
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 5

4. (F342) ASD CONTROL OUTPUT CIRCUIT(S) OPEN
1. Turn the ignition off.
2. Measure the resistance of each (F342) ASD Control Output circuits from the PDC harness to the appropriate terminals of PCM harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 3

No

- Repair the open in the (F342) ASD Control Output circuit(s).
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

5. POWER DISTRIBUTION CENTER
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the related PDC and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the PDC and Powertrain Control Module connectors.
4. Perform any Technical Service Bulletins that may apply.

Were there any problems found?

Yes

- Repair as necessary.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Replace and program the Power Distribution Center.
- Perform the BODY VERIFICATION TEST. Body Verification Test.