When IG key OFF signal is inputted to ECM. ECM stops injector operation and engine turns OFF. Then, After-run (turning off process of ECM internal system) is performed in order to shut system down. During this process, if main relay power supply is cut too late or power supply is cut too early before After-run process completes, ECM detect main relay error and P0685 is set.
Item | Detecting Condition | Possible Cause | ||
DTC Strategy |
•
Voltage monitoring | 1. Main relay circuit 2. Main relay component | ||
Enable Conditions |
•
Engine running | |||
Threshold value |
•
When main relay respond to IG key - ON/OFF signal too fast or slow. - After-run finished and it requires more than 2 sec. for main relay to be deactivated. - Main relay deactivated before after-run finished more than 3 times. | |||
Diagnosis Time |
•
Immediately | |||
Fail Safe | Fuel cut | NO |
•
- | |
EGR Off | NO | |||
Fuel Limit | NO | |||
Check Lamp | OFF | |||
