P068B-ASD/MAIN RELAY OFF TOO LATE
For a complete wiring diagram Refer to Section 8W
- When Monitored:
When the ignition is turned off, during AFTER-RUN mode of operation.
- Set Condition:
The internal ECM timer determines that the Main Relay remained on too long once AFTER-RUN mode of operation has been completed.
| Possible Causes |
| CHECK FOR OTHER DTCS |
| INTERMITTENT CONDITION |
| SUBSTITUTE MAIN RELAY |
| (K51) MAIN RELAY CONTROL CIRCUIT SHORTED TO GROUND INTERMITTENTLY |
| (K542) MAIN RELAY OUTPUT CIRCUIT SHORTED TO VOLTAGE |
| ENGINE CONTROL MODULE |
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)
Diagnostic Test
1. CHECK FOR OTHER DTCSTurn the ignition on.
With the scan tool, check for additional DTCs.
Are other DTCs present?
Yes
- Refer to the Symptom List for diagnosis of the other DTCs before continuing.
- Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)
No
- Go To2
2. CLEAR CODE AND CHECK IF THE DTC RESETS
Perform several ignition key cycles, pausing for at least 10 seconds between each cycle.
Turn the ignition on.
With the scan tool, read ECM DTCs.
Did this DTC set again?
Yes
- Go To 3
No
- Go To 6
3. MAIN RELAY
Turn the ignition off.
Install a known good relay in place of the Main Relay.
Turn the ignition on.
With the scan tool, erase DTCs.
Perform several ignition key cycles, pausing for at least 10 seconds between each cycle.
Turn the ignition on.
With the scan tool, read ECM DTCs.
Did this DTC set again?
Yes
- Go To 4
No
- Replace the Main Relay.
- Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)
4. (K51) MAIN RELAY CONTROL CIRCUIT SHORTED TO GROUND INTERMITTENTLY
Turn the ignition off.
Remove the Main Relay.
Disconnect the ECM harness connectors.
Measure the resistance between ground and the (K51) Main Relay Control circuit while wiggling the wiring harness and connectors between the ECM and Main connector.
Was the resistance below 1000 ohms at any time while wiggling the wiring harness and connectors?
Yes
- Repair the (K51) Main Relay Control circuit for an intermittent short to ground.
- Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)
No
- Go To 5
5. (K542) MAIN RELAY OUTPUT CIRCUIT SHORTED TO VOLTAGE
Turn the ignition on.
Measure the voltage of the (K542) Main Relay Output circuit at the Main Relay connector.
Is the voltage below 1.0 volt?
Yes
- Replace and program the Engine Control Module in accordance with the Service Information.
- Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)
No
- Repair the (K542) Main Relay Output circuit for a short to voltage.
- Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)
6. INTERMITTENT CONDITION
WARNING: WHEN THE ENGINE IS OPERATING, DO NOT STAND IN A DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE PULLEYS, BELTS OR FAN. DO NOT WEAR LOOSE CLOTHING.
NOTE: The conditions that set the DTC are not present at this time. The following list may help in identifying the intermittent condition.
With the engine running at normal operating temperature, monitor the scan tool parameters related to the DTC while wiggling the wiring harness. Look for parameter values to change and/or a DTC to set.
Review the DTC When Monitored and Set Conditions. If possible, try to duplicate the conditions under which the DTC was set.
Refer to any Technical Service Bulletins (TSB) that may apply.
Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or partially broken wires.
Visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals.
Were any of the above conditions present?
Yes
- Repair as necessary.
- Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)
No
- Test Complete.