Pinpoint Test Y: The Reversing Lamps Are On Continuously
Reversing Lamps
Pinpoint Tests
Pinpoint Test Y: The Reversing Lamps Are On Continuously
Refer to Wiring Diagram Set 93, Reversing Lamps for schematic and connector information. 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 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. 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 indicating the transmission is in reverse.
- DTC B1277:15 (Reverse Lamp: Circuit Short To Battery or Open) - sets when the BCM-B detects a short to voltage from one of the reversing lamp output circuits.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Reversing lamp switch (manual transmission)
- BCM-B
- PCM
PINPOINT TEST Y: 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.
-------------------------------------------------
Y1 CHECK FOR BCM-B DTC B1272:15
- Ignition OFF.
- Review the results from the BCM-B self-test.
- Is DTC B1272:15 present?
Yes
GO to Y2.
No
GO to Y3.
-------------------------------------------------
Y2 CHECK THE BCM-B REVERSING LAMP OUTPUT CIRCUITS FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: BCM-B C4368a.
- Ignition ON.
- Do the reversing lamps continue to illuminate?
Yes
REPAIR circuit CLS10 (GN/BN) (LH reverse lamp) or circuit CLS11 (GY/VT) (RH reverse lamp) for a short to voltage. CLEAR the DTCs. REPEAT the self-test.
No
GO to Y6.
-------------------------------------------------
Y3 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 Y4.
-------------------------------------------------
Y4 CHECK THE REVERSING LAMP SWITCH
- Ignition OFF.
- Disconnect: Reversing Lamp Switch C169.
- Ignition ON.
- Do the reversing lamps continue to illuminate?
Yes
GO to Y5.
No
INSTALL a new reversing lamp switch. REFER to Reversing Lamp Switch Service and Repair. TEST the system for normal operation.
-------------------------------------------------
Y5 CHECK THE REVERSING LAMP SWITCH INPUT CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: PCM C175t.
- Measure the resistance between the reversing lamp switch C169-A, circuit CET47 (BU), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to Y7.
No
REPAIR circuit CET47 (BU) for a short to ground. TEST the system for normal operation.
-------------------------------------------------
Y6 CHECK FOR CORRECT BCM-B OPERATION
- Disconnect all the BCM-B connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the BCM-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. REFER to Body Control Systems. 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.
-------------------------------------------------
Y7 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 Computers and Control Systems. 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.
-------------------------------------------------