P0688
P0688-ASD RELAY CONTROL SENSE
Special Tools:
For a complete wiring diagram, refer to the Wiring Information.
For specific relay location and type, Locations.
- When Monitored:
With ignition key on. Battery voltage greater than 10.0 Volts.
- Set Condition:
The Powertrain Control Module (PCM) detects an open or short to ground in the (K51) ASD Relay control circuit. One Trip Fault. Three good trips to turn off the MIL.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. PCM Pre-Diagnostic Troubleshooting Procedure
Diagnostic Test
1. VERIFY ASD 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 Control
- ASD Control Output (TIPM DTC)
1. With the scan tool, erase the DTC.
2. Attempt to start the engine. If the engine will not start, crank the engine for at least 15 seconds. It may be necessary to repeat several times.
Does the DTC return?
Yes
- Go To 2
No
- Perform the INTERMITTENT CONDITION diagnostic procedure. PCM Intermittent Condition Test.
2. ASD RELAY
1. Turn the ignition off.
2. Install a substitute relay in place of the ASD Relay.
3. Ignition on, engine not running.
4. With the scan tool, erase DTCs.
5. Attempt to start the engine.
6. With the scan tool, select View DTCs.
Does the DTC return?
Yes
- Go To 3
No
- Replace the ASD Relay.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
3. CHECK THE (K51) ASD RELAY CONTROL CIRCUIT FOR AN OPEN
1. Turn the ignition off.
2. Remove the ASD Relay.
3. Disconnect the C1 PCM 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 GPEC Diagnostic Adaptor to perform the diagnosis.
4. Connect the (10436).
5. Measure the resistance of the (K51) ASD Relay Control circuit from the Relay connection to the GPEC Adaptor.
Is the resistance below 5.0 Ohms?
Yes
- Go To 4
No
- Repair the (K51) ASD Relay Control circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
4. CHECK THE (K51) ASD RELAY CONTROL CIRCUIT FOR A SHORT TO GROUND
1. Measure the resistance between ground and the (K51) ASD Relay Control circuit at terminal 85 of the ASD Relay connector.
Is the resistance above 10k Ohms?
Yes
- Go To 5
No
- Repair the (K51) ASD Relay Control circuit for a short to ground.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
5. CHECK THE (A14) FUSED B+ CIRCUIT
1. Turn the ignition off.
2. Using a 12-volt test light connected to ground, probe the (A14) Fused B+ circuit at the Relay connection.
NOTE: The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.
Does the test light illuminate brightly?
Yes
- Go To 6
No
- Repair the open or short to ground in the (A14) Fused B+ circuit. Inspect the related fuse and repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
6. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the ASD Relay 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 ASD Relay 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 POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Replace and program the Powertrain Control Module. Powertrain Control Module - Removal.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.