Pinpoint Test W: The Reversing Lamps Are On Continuously
Reversing Lamps
Pinpoint Tests
Pinpoint Test W: The Reversing Lamps Are On Continuously
Refer to Wiring Diagram Set 93, Reversing Lamps for schematic and connector information. Diagrams By Number
Normal Operation
The PCM (gasoline engine) or the Transmission Control Module (TCM) (diesel engine) monitors the transmission. When the transmission is in REVERSE, the PCM or Transmission Control Module (TCM) 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 receives the message indicating the transmission is in REVERSE, the BCM provides voltage to the reversing lamps.
On vehicles with a manual transmission, the reversing lamp switch is monitored by the PCM.
- DTC B1277:15 (Reverse Lamp: Circuit Short To Battery or Open) - a DTC that sets when the BCM detects a short to voltage from the reversing lamp output circuit.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Reversing lamp switch
- BCM
PINPOINT TEST W: 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.
-------------------------------------------------
W1 CHECK THE BCM CONTROL OF THE REVERSING LAMPS
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: BCM DataLogger.
- Select the BCM reverse lamps active command (RVRS_LMPS). Command the reverse lamps off.
- Do the reversing lamps turn off?
Yes
If equipped with an automatic transmission, REFER to Automatic Transaxle/Transmission - TorqShift(R) or Automatic Transaxle/Transmission - TorqShift(R)6 Testing and Inspection to diagnose a Transmission Range (TR) concern. If equipped with a manual transmission, GO to W3.
No
GO to W2.
-------------------------------------------------
W2 CHECK THE BCM OUTPUT
- Ignition OFF.
- Disconnect: BCM C2280d.
- Ignition ON.
- Do the reversing lamps continue to illuminate?
Yes
REPAIR circuit CLS28 (BU/WH) for a short to voltage. TEST the system for normal operation.
No
GO to W6.
-------------------------------------------------
W3 CHECK THE REVERSING LAMP SWITCH
- Ignition OFF.
- Disconnect: Reversing Lamp Switch C169.
- Ignition ON.
- Do the reversing lamps continue to illuminate?
Yes
GO to W4.
No
INSTALL a new reversing lamp switch. TEST the system for normal operation.
-------------------------------------------------
W4 CHECK THE REVERSING LAMP SWITCH INPUT CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: PCM C175t .
- Ignition ON.
- Measure the resistance between the PCM C175t-7, circuit CET47 (GY/OG or BU), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to W5.
No
REPAIR circuit CET47 (GY/OG or BU) for a short to ground. TEST the system for normal operation.
-------------------------------------------------
W5 CHECK FOR CORRECT PCM OPERATION
- Disconnect all the PCM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the PCM 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 PCM. REFER to Electronic Engine Controls - Gasoline Engines Service and Repair. 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.
-------------------------------------------------
W6 CHECK FOR CORRECT BCM OPERATION
- Disconnect all the BCM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the BCM 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. REFER to Multifunction Electronic Modules Service and Repair. 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.
-------------------------------------------------