Pinpoint Test AD: The Reversing Lamps Are On Continuously
Reversing Lamps
Pinpoint Test AD: The Reversing Lamps Are On Continuously
Refer to Wiring Diagram Set 93, Reversing Lamps for schematic and connector information Electrical Diagrams.
Normal Operation
The PCM monitors the transmission. When the transmission is in reverse, the PCM sends a message to the Body Control Module (BCM) over the High Speed Controller Area Network (HS-CAN) indicating the transmission is in reverse. When the BCM (Body Control Module) receives the message indicating the transmission is in reverse, the BCM (Body Control Module) provides voltage to the reversing lamps and the auto-dimming interior rear view mirror.
- DTC B1277:15 (Reverse Lamp: Circuit Short To Battery or Open)- a DTC that sets when the BCM (Body Control Module) detects a short to voltage from the reversing lamp output circuit.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Auto-dimming interior rear view mirror
- BCM (Body Control Module)
PINPOINT TEST AD : THE REVERSING LAMPS ARE ON CONTINUOUSLY
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
AD1 CHECK THE BCM (Body Control Module) CONTROL OF THE REVERSING LAMPS
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: BCM (Body Control Module) DataLogger.
- Select the BCM (Body Control Module) reverse lamps active command (RVRS_LMPS). Command the reverse lamps off.
Do the reversing lamps turn off?
Yes
REFER to Automatic Transmission/Transaxle &/or Transmission Control Systems to diagnose a Transmission Range (TR) concern.
No
GO to AD2.
AD2 CHECK THE BCM (Body Control Module) OUTPUT
- Ignition OFF.
- Disconnect: BCM (Body Control Module) C2280D.
- Ignition ON.
Do the reversing lamps continue to illuminate?
Yes
GO to AD3.
No
GO to AD4.
AD3 CHECK THE AUTO-DIMMING INTERIOR REAR VIEW MIRROR
- Ignition OFF.
- Disconnect: Auto-Dimming Interior Rear View Mirror C911.
- Ignition ON.
Do the reversing lamps continue to illuminate?
Yes
GO to AD4.
No
INSTALL a new auto-dimming interior rear view mirror. TEST the system for normal operation.
AD4 CHECK FOR CORRECT BCM (Body Control Module) OPERATION
- Disconnect all the BCM (Body Control Module) connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the BCM (Body Control Module) connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
Is the concern still present?
Yes
INSTALL a new BCM (Body Control Module). TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.