Pinpoint Test W: All The Reversing Lamps Are Inoperative
Reversing Lamps
Pinpoint Test W: All The Reversing Lamps Are Inoperative
Refer to Wiring Diagram Set 11, Fuse and Relay Information for schematic and connector information [1][2]Diagrams By Number.
Refer to Wiring Diagram Set 93, Reversing Lamps for schematic and connector information [1][2]Diagrams By Number.
Normal Operation
When the Body Control Module B (BCM-B) receives a message from the PCM indicating the transmission is in reverse, the BCM-B (Body Control Module B) supplies voltage to the reversing lamps.
Automatic Transmission
The PCM monitors the gear status from the transmission. When the transmission is in REVERSE (R), a message is sent to the BCM-B (Body Control Module B). If any gear status concerns exist, the PCM sets a DTC and the wrench indicator turns on.
Manual Transmission
The PCM sends a voltage signal to the reversing lamps switch. When the transmission is in REVERSE (R), the voltage signal is routed back to the PCM and the PCM sends a message to the BCM-B (Body Control Module B) indicating the transmission is in reverse.
- DTC B1277:11 (Reverse Lamp: Circuit Short To Ground)- sets when the BCM-B (Body Control Module B) detects a short to ground from one of the reversing lamp output circuits.
- DTC B1277:15 (Reverse Lamp: Circuit Short To Battery or Open)- sets when the BCM-B (Body Control Module B) detects an open from both reversing lamp output circuits.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Reversing lamps switch (manual transmission)
- PCM
- BCM-B (Body Control Module B)
PINPOINT TEST W : ALL THE REVERSING LAMPS ARE INOPERATIVE
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
W1 CARRY OUT THE BCM-B (Body Control Module B) REVERSING LAMP CONTROL ACTIVE COMMAND USING THE SCAN TOOL
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: BCM-B (Body Control Module B) DataLogger.
- Select the BCM-B (Body Control Module B) reversing lamp (REVERSE_LMP) active command. Command the reversing lamp on and off.
Do the reversing lamps turn on when commanded on?
Yes
GO to W7.
No
GO to W2.
W2 CHECK FOR THE BCM-B (Body Control Module B) REVERSE LAMP SHORT TO GROUND DTC
- Ignition OFF.
- Review the results from the BCM-B (Body Control Module B) self-test.
Is DTC B12772:11 present?
Yes
GO to W4.
No
GO to W3.
W3 CHECK THE STOPLAMP OPERATION
- Apply and release the brake pedal while observing the stoplamps.
Do the stoplamps operate correctly?
Yes
GO to W11.
No
REFER to Stoplamps Testing and Inspection.
W4 ISOLATE THE LH REAR LAMP SHORT TO GROUND
- Disconnect: LH Rear Lamp C498.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: BCM-B (Body Control Module B) Self-Test.
- Clear the DTCs and repeat the self-test (required to enable the stoplamp output driver if DTC U1000:00 is present).
Is DTC B12772:11 still present?
Yes
GO to W5.
No
REPAIR or INSTALL a new LH rear lamp jumper harness. TEST the system for normal operation.
W5 ISOLATE THE RH REAR LAMP SHORT TO GROUND
- Ignition OFF.
- Disconnect: RH Rear Lamp C499.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: BCM-B (Body Control Module B) Self-Test.
- Clear the DTCs and repeat the self-test (required to enable the stoplamp output driver if DTC U1000:00 is present).
Is DTC B12772:11 still present?
Yes
GO to W6.
No
REPAIR or INSTALL a new RH rear lamp jumper harness. TEST the system for normal operation.
W6 CHECK THE BCM-B (Body Control Module B) REVERSE LAMP OUTPUT CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: BCM-B (Body Control Module B) C4368A.
- Measure the resistance between the LH rear lamp C498-1, circuit CLS10 (GN/BN), harness side and ground; and between the RH rear lamp C499-1, circuit CLS11 (GY/VT), harness side and ground.
Are the resistances greater than 10,000 ohms?
Yes
GO to W11.
No
REPAIR the circuit in question for a short to ground. After the repair:
If no DTCs are present, TEST the system for normal operation.
If DTC U1000:00 is present, CLEAR the DTCs and REPEAT the self-test (required to enable the stoplamp output driver). TEST the system for normal operation.
If DTC U3000:49 is present, INSTALL a new SJB (Smart Junction Box). TEST the system for normal operation.
W7 CHECK FOR PCM DTCs
- Ignition ON.
- Disconnect: PCM Self-Test.
- Carry out the PCM Key ON Engine OFF (KOEO) and Key ON Engine Running (KOER) self-tests.
Are any PCM DTCs present?
Yes
REFER to Body Control Systems or Computers and Control Systems Information as necessary.
No
For vehicles with an automatic transmission, REFER to Automatic Transmission/Transaxle &/or Transmission Control Systems to diagnose a Transmission Range (TR) input concern.
For vehicles with a manual transmission, GO to W8.
W8 BYPASS THE REVERSING LAMP SWITCH
- Ignition OFF.
- Disconnect: Reversing Lamp Switch C169 (3.7L or 5.0L engine) or C1131 (5.4L engine).
- For vehicles with a 3.7L or 5.0L engine, connect a fused jumper wire between the reversing lamp switch C169-1, circuit CET47 (BU), harness side and the reversing lamp switch C169-2, circuit RE405 (GN/WH), harness side.
- For vehicles with a 5.4L engine, connect a fused jumper wire between the reversing lamp switch C1131-A, circuit CET47 (BU), harness side and the reversing lamp switch C1131-B, circuit RE405 (GN/WH), harness side.
- Ignition ON.
Do the reversing lamps illuminate?
Yes
REMOVE the jumper wire. INSTALL a new reversing lamp switch. REFER to Reversing Lamp Switch . TEST the system for normal operation.
No
REMOVE the jumper wire. GO to W9.
W9 CHECK THE REVERSING LAMP SWITCH INPUT
- Ignition OFF.
- Connect: Reversing Lamp Switch C169 (3.7L or 5.0L engine) or C1131 (5.4L engine).
- Disconnect: PCM C1381T (3.7L engine) or C175T (5.0L or 5.4L engine).
- Select REVERSE.
- For vehicles with a 3.7L engine, measure the resistance between the PCM C1381T-17, circuit CET47 (BU), harness side and the PCM C1381T-41, circuit RE406 (GY/VT), harness side.
- For vehicles with a 5.0L or 5.4L engine, measure the resistance between the PCM C175T-7, circuit CET47 (BU), harness side and the PCM C175T-38, circuit RE406 (GY/VT), harness side.
Is the resistance less than 5 ohms?
Yes
GO to W12.
No
GO to W10.
W10 CHECK THE REVERSING LAMP SWITCH CIRCUITS FOR AN OPEN
- Disconnect: Reversing Lamp Switch C169 (3.7L or 5.0L engine) or C1131 (5.4L engine).
- For vehicles with a 3.7L engine, measure the resistance between the PCM C1381T-17, circuit CET47 (BU), harness side and the reversing lamp switch C169-1, circuit CET47 (BU), harness side.
- For vehicles with a 5.0L engine, measure the resistance between the PCM C175-7, circuit CET47 (BU), harness side and the reversing lamp switch C169-1, circuit CET47 (BU), harness side.
- For vehicles with a 5.4L engine, measure the resistance between the PCM C175-7, circuit CET47 (BU), harness side and the reversing lamp switch C1131-A, circuit CET47 (BU), harness side.
Is the resistance less than 5 ohms?
Yes
REPAIR circuit RE406 (GY/VT) for an open. TEST the system for normal operation.
No
REPAIR circuit CET47 (BU) for an open. TEST the system for normal operation.
W11 CHECK FOR CORRECT BCM-B (Body Control Module B) OPERATION
- Disconnect all the BCM-B (Body Control Module B) connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the BCM-B (Body Control Module B) 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-B (Body Control Module B). 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. CLEAR the DTCs. REPEAT the self-test.
W12 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. 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.