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 relay is energized. One Trip Fault. Three good trips to turn off the MIL.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Initial Inspection and Diagnostic Overview .


Diagnostic Test


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 DTC(s) have set along with P0688, diagnose them first before continuing.Ignition Coil(s)Fuel Injector(s)ASD ControlASD Control Output (TIPM DTC)

Ignition on, engine not running.
With a scan tool, select View DTCs.
Is the DTC Active at this time?

Yes


- Go To 2


No


- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition



2. ASD CONTROL OUTPUT OPERATION FROM THE TIPM




Turn the ignition off.
Disconnect the C1 and C3 PCM harness connectors.

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.

Ignition on, engine not running.
With a 12-volt test light connected to ground, probe both of the (K342) ASD Control Output circuits in the appropriate terminals of special tool #8815.
Using the scan tool in the TIPM, actuate the ASD Control Output.
Does the test light illuminate brightly and flash on an off?

Yes


-
NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.
If OK, replace the PCM. Engine Control Module


No


- Go To 3



3. (K342) ASD CONTROL OUTPUT CIRCUIT(S) OPEN




Turn the ignition off.
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 Miller Special Tool #8815 to perform diagnosis.

Measure the resistance of both the (K342) ASD Control Output circuits from the C1 TIPM harness connector to the appropriate terminals of special tool #8815.
Is the resistance below 5.0 ohms?

Yes


- Go To 4


No


- Repair the open in the (K342) ASD Control Output circuit(s).
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test



4. (K342) ASD CONTROL OUTPUT CIRCUIT(S) SHORTED TO GROUND




Measure the resistance between ground and both of the (K342) ASD Control Output circuits in the C1 TIPM harness connector.
Is the resistance below 100 ohms?

Yes


- Repair the short to ground in the (K342) ASD Control Output circuit(s).
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test


No


- Go To 5



5. TOTALLY INTEGRATED POWER MODULE
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the related TIPM and the Powertrain Control Module (PCM).
Look for any chafed, pierced, pinched, or partially broken wires.
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.
Refer to any Technical Service Bulletins that may apply.
Were there any problems found?

Yes


- Repair as necessary.
- Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test


No


- Replace and program the Totally Integrated Power Module.
- Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test