The voltage after the fuel pump relay is used to supply power to the electric fuel pump in the low pressure line.
When the ignition switch is in starting position, the battery voltage is supplied from the fuel pump relay to the ECM.
When the ignition switch is turned on, current flows from the ignition switch through the current the fuel pump relay coil to ground by the ECM. And then, the voltage is supplied to the electric fuel pump to drive.
In case of the fuel pump relay failure, the engine symptoms will occur the running engine stall and the starting impossible.
If the signal exceeds threshold value, the ECM judged this as a fault and DTC is set.
Item | Detecting Condition | Possible Cause |
DTC Strategy | ● Circuit continuity check | ● Contact resistance in connectors ● Open in power circuit ● Open or short to ground in relay control circuit ● Fuse blown ● Faulty relay ● Faulty ECM |
Enable Conditions | ● Ignition on | |
Threshold Value | ● Open or short for relay control circuit | |
Diagnostic Time | ● 0.48 sec. | |
MIL Fuel Limit Fuel Cut EGR Off | ● No ● No ● No ● No |
