P068B-ECM RELAY OFF TOO LATE





For a complete wiring diagram Refer to Section 8W

Theory of Operation


When the ignition switch is turned off (ignition power removed from ECM) the ECM continues to drive the ECM/ASD relay on for approximately 20–40 seconds. This period of time is the After-Run Mode of operation. During After-Run the ECM performs several internal and external checks. When After-Run is complete, the ECM switches off the ECM/ASD relay driver and powers off the engine system.



Possible Causes
CHECK FOR OTHER DTCS
INTERMITTENT CONDITION
SUBSTITUTE ASD RELAY
(K51) ASD RELAY CONTROL CIRCUIT SHORTED TO GROUND INTERMITTENTLY
ASD 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 DTCS

Turn the ignition on.
With the scan tool, check for additional DTCs.

Are other DTCs present?

Yes


No

2. CLEAR CODE AND CHECK IF THE DTC RESETS

Perform several ignition key cycles, pausing for at least 40 seconds between each cycle.
Turn the ignition on.
With the scan tool, read ECM DTCs.

Did this DTC set again?

Yes


No

3. ASD RELAY

Turn the ignition off.
Install a known good relay in place of the ASD Relay.
Turn the ignition on.
With the scan tool, erase DTCs.
Perform several ignition key cycles, pausing for at least 40 seconds between each cycle.
Turn the ignition on.
With the scan tool, read ECM DTCs.

Did this DTC set again?

Yes


No

4. (K51) ASD RELAY CONTROL CIRCUIT SHORTED TO GROUND INTERMITTENTLY



Turn the ignition off.
Remove the ASD Relay from the TIPM.
Disconnect the ECM harness connectors.
Measure the resistance between ground and the (K51) ASD Relay Control circuit while wiggling the wiring harness and connectors.

Was the resistance below 1000 ohms at any time while wiggling the wiring harness and connectors?

Yes


No

5. ASD RELAY OUTPUT CIRCUIT SHORTED TO VOLTAGE

Turn the ignition on.
Measure the voltage of the ASD Relay Output circuit.

Is the voltage below 1.00 volt?

Yes


No

6. CHECK THE ECM POWER AND GROUND CIRCUITS

Turn the ignition off.
Install the ASD relay.
Refer to symptom CHECKING THE ECM POWER AND GROUNDS and verify proper Ignition, Battery and Ground circuits at the ECM.

Were any problem found with the ECM Ignition, Battery or Ground circuits?

Yes


No