The PCM provides ground to one side of the coil of the main relay and the other side is connected to the battery. The PCM monitors battery voltage and the voltage after the main relay.
Checking the contolling state of main relay every 10 sec. under detecting condition, if open or short in the circuit is detected for more than 5 sec., PCM sets P0685.
Item | Detecting Condition | Possible cause |
DTC Strategy | ● Detects a short to ground, to battery or open circuit on the main relay | ● Poor Connection ● Open or short in control circuit. ● Faulty Main Relay ● Faulty PCM |
Enable Conditions | ● Engine Running ● 11V ≤ Ignition Voltage ≤ 16V | |
Threshold value | ● Open or Short in circuit | |
Diagnosis Time | ● Contineous (More than 5sec. failure for every 10 sec. test) | |
MIL On Condition | ● DTC only (NO MIL ON) |
If Main relay has a fault(ex. Open) under engine running, the DTCs,P0638/P0685/P1295/P2106, can happen at the same time.
<DTC Name>
- P0638 Throttle Actuator Control Range/Performance(Bank 1)
- P0685 PCM/PCM Power Relay Control Circuit /Open
- P1295 Throttle Actuator Control System - Power Management
- P2106 Throttle Actuator Control System - Forced Limited Power
Coil Resistance | 70Ω ~ 120Ω |
