Test T: Both Reversing Lamps Are Inoperative

PINPOINT TEST T: BOTH REVERSING LAMPS ARE INOPERATIVE

Normal Operation - Manual Transmission
The powertrain control module (PCM) sends a voltage reference signal to the reversing lamp switch through circuit 1789 (VT/WH). When the transmission is placed in REVERSE (R), the reversing lamp switch closes and routes the signal back to the PCM through circuit 359 (GY/RD). The PCM then sends a message to the smart junction box (SJB), through the instrument cluster (IC) gateway function, over the communication network. The SJB then provides voltage to the reversing lamps. The SJB is provided voltage from the bussed electrical center (BEC) through circuit 1679 (WH/YE) to power the reversing lamps.

Normal Operation - Automatic Transmission
When the PCM detects the transmission is in REVERSE (R), a message is sent to the SJB, through the instrument cluster (IC) gateway function, over the communication network. The SJB then provides voltage to the reversing lamps. The SJB is provided voltage from the BEC through circuit 1679 (WH/YE) to power the reversing lamps The PCM sets DTCs if any faults with the digital transmission range (TR) sensor inputs are detected.

This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Reversing lamp switch (manual transmission)
- Digital transmission range (TR) sensor input (automatic transmission) concern
- BEC
- SJB
- PCM

T1-T2:

T2-T3:

T3-T5:

T5-T7: