P0688
P0688-ASD/MAIN SENSE CIRCUIT
- When Monitored:
With the control circuit active and battery voltage greater than 10.4 volts.
- Set Condition:
The Powertrain Control Module (PCM) detects that the (F342) ASD Relay Output circuit voltage is not within the specified range based on operation conditions.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.
1. DTC IS ACTIVE
1. Turn the ignition on.
2. With the scan tool, Clear DTCs in the Powertrain Control Module (PCM).
3. With the scan tool, actuate the Auto Shutdown (ASD) Relay Control State.
4. With the scan tool, select View DTCs.
Is the status Active for this DTC?
Yes
- Go To 2
No
- Perform the CHECKING FOR AN INTERMITTENT DTC diagnostic procedure. Checking for an Intermittent DTC.
2. FUSED B(+) CIRCUIT OPEN OR HIGH RESISTANCE
1. Turn the ignition off.
2. Remove the Auto Shutdown Relay.
3. Turn the ignition on.
4. Using a 12-volt test light connected to ground, check both Fused B(+) circuits in the Auto Shutdown Relay connector.
NOTE: The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.
Is the test light illuminated and bright?
Yes
- Go To 3
No
- Repair the Fused B(+) circuit for an open circuit or high resistance.
- Perform the PCM VERIFICATION TEST. PCM Verification Test.
3. (F342) ASD RELAY OUTPUT CIRCUIT SHORTED TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the Powertrain Control Module (PCM) harness connectors.
3. Turn the ignition on.
4. Measure the voltage of each of the (F342) ASD Relay Output circuits in the Auto Shutdown Relay connector.
Is there any voltage present?
Yes
- Repair the (F342) ASD Relay Output circuit for a short to voltage.
- Perform the PCM VERIFICATION TEST. PCM Verification Test.
No
- Go To 4
4. (F342) ASD RELAY OUTPUT CIRCUIT SHORTED TO GROUND
1. Turn the ignition off.
2. Measure the resistance between ground and the (F342) ASD Relay Output circuit in the Auto Shutdown Relay connector.
Is the resistance below 100 Ohms?
Yes
- Repair the (F342) ASD Relay Output circuit for a short to ground.
- Perform the PCM VERIFICATION TEST. PCM Verification Test.
No
- Go To 5
5. (F342) ASD RELAY OUTPUT CIRCUIT OPEN OR HIGH RESISTANCE
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 8815 to perform diagnosis.
1. Measure the resistance of the (F342) ASD Relay Output circuits between the Auto Shutdown Relay connector and each of the appropriate terminals of PCM Pinout Box 8815.
Is the resistance below 5.0 Ohms?
Yes
- Go To 6
No
- Repair the (F342) ASD Relay Output circuit for an open circuit or high resistance.
- Perform the PCM VERIFICATION TEST. PCM Verification Test.
6. AUTO SHUTDOWN RELAY
1. Turn the ignition off.
2. Install the Auto Shutdown Relay.
3. Connect the Powertrain Control Module (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 the PCM Pinout Box 8815 along with the Adapter 8815-1 to perform the diagnosis.
4. Turn the ignition on.
5. With the scan tool, actuate the Auto Shutdown (ASD) Relay Control State.
6. Measure the voltage of each of the (F342) ASD Relay Output circuits in the appropriate terminals of PCM Pinout Box 8815-1.
NOTE: If the DTC is active, the actuation test may not be allowed by the PCM. If may be necessary to clear the DTCs before starting the actuation.
NOTE: The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.
Is the test light illuminated and bright for each of the circuits during the actuation?
Yes
- Go To 7
No
- Replace the Auto Shutdown Relay.
- Perform the PCM VERIFICATION TEST. PCM Verification Test.
7. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Auto Shutdown 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.
4. Perform any Technical Service Bulletins (TSBs) that may apply.
Were any problems found?
Yes
- Repair as necessary.
- Perform the PCM VERIFICATION TEST. PCM Verification Test.
No
- Replace and program the Powertrain Control Module (PCM).
- Perform the PCM VERIFICATION TEST. PCM Verification Test.