Pinpoint Test C : The Message Center Displays Wiring Fault On Trailer: Notes
Refer to Trailer/Camper Adapter , for schematic and connector information.
Normal Operation and Fault Conditions
The braking energy provided to the trailer is modulated with a PWM signal which varies between 0 volts and battery voltage, the higher the duty cycle the more braking power available. The TBC module varies the PWM signal based on various inputs such as the brake torque message, the manual slider switch and the gain buttons. With the vehicle stationary and with the manual slider switch fully to the left with a gain of 10, there should be more than 10 volts supplied to pin 3 of the 7-pin trailer tow connector. When a trailer is connected to the vehicle the IPC should show the TRAILER CONNECTED message. If the WIRING FAULT ON TRAILER message is only displayed when the trailer is connected the fault is with the trailer wiring.
Every 4 seconds (when not braking) the TBC module sends a voltage pulse to pin 3 of the 7-pin trailer tow connector for a TBC module output circuit diagnostic test.
DTC Fault Trigger Conditions
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| B148A:11 | Trailer Brake Output: Circuit Short to Ground | This DTC sets in continuous memory and on-demand when the TBC module detects trailer brake DC voltage output is 60 percent less than expected or the trailer brakes are drawing more than 27 amps during a braking event. The TBC module disables the trailer brake output and then shuts down. |
| B148A:12 | Trailer Brake Output: Circuit Short To Battery | This DTC sets in continuous memory when the TBC module output is greater than 7.1 volts while not braking with vehicle speed greater than 3 km/h (2 mph). The TBC module disables the trailer brake output and then shuts down. |
Possible Causes
- Wiring, terminals or connectors
- TBC module
- Trailer