When IG KEY OFF signal is imput to the ECM. The ECM stops injector operation. Then, After-run(turning off process of ECM intermal 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, the ECM detect main relay error and P0685 is set.
Item | Detecting Condition | Possible Cause | |
DTC Strategy |
•
Voltage monitoring | 1. Main relay open or short to ground 2. Faulty main relay | |
Enable Conditions |
•
IG "ON" & Engine "ON" | ||
Threshold Value |
•
Main relay circuit error | ||
Fail Safe | Fuel Cut |
•
NO | |
EGR Off |
•
NO | ||
Fuel Limit |
•
NO | ||
Check Lamp |
•
NO | ||
