P0688

P0688-AUTO SHUTDOWN SENSE CIRCUIT LOW

Special Tools:










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 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 O2 SENSOR HEATER CIRCUIT HIGH DTCs set along with P0688-AUTO SHUTDOWN RELAY SENSE CIRCUIT LOW, all of the O2 Sensor Heater Control circuits need to be checked for a short to battery voltage.

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 ControlASD Control Output (TIPM DTC)

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. ASD RELAY
1. Turn the ignition off.
2. Install a known good relay in place of the existing ASD Relay.
3. Attempt to start the engine.

Does the engine start with no codes?

Yes

- Replace the ASD Relay.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 3

3. (F342) ASD RELAY CONTROL CIRCUIT(S) OPEN




1. Turn the ignition off.
2. Disconnect the C1 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 the PCM Pinout Box (8815A) to perform diagnosis.

3. Measure the resistance of both the (F342) ASD Relay Output circuits from the C1 TIPM harness connector to the appropriate terminals of PCM Pinout Box.

Is the resistance below 5.0 Ohms?

Yes

- Go To 4

No

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

4. (F342) ASD RELAY OUTPUT CIRCUIT(S) SHORTED TO GROUND




1. Measure the resistance between ground and any of the (F342) ASD Relay Output circuits at the appropriate terminal of the PCM Pinout Box.

Is the resistance below 10k Ohms?

Yes

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

No

- Go To 5

5. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the related TIPM 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 TIPM and Powertrain Control Module connectors.
4. Search for any Technical Service Bulletins that may apply.

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 (PCM).
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.