B3903
DTC B3903
CIRCUIT DESCRIPTION
The electronic brake control module (EBCM) supplies voltage to the brake pedal position sensor relay coil side voltage supply circuit when the stop lamps are active. The coil side control circuit of the brake pedal position sensor relay is permanently grounded at G402.
DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC B3903 Stoplamp Relay Circuit
CONDITIONS FOR RUNNING THE DTC
- The EBCM control module must be powered.
- This test is run continuously.
CONDITIONS FOR SETTING THE DTC
If the brake pedal position sensor relay coil side voltage supply circuit is out of range for more than 30 milliseconds.
ACTION TAKEN WHEN THE DTC SETS
When DTC B3903 is set the following will occur:
The service vehicle soon lamp will illuminate.
CONDITIONS FOR CLEARING THE DTC
- The current DTC will clear when the fault is no longer present.
- The ignition key must be cycled OFF and ON.
- A history DTC clears after 100 consecutive ignition cycles in which no faults have occurred.
- Clear the DTC with a scan tool
TEST
