Pinpoint Test T: The Reversing Lamps Are On Continuously
Reversing Lamps
Pinpoint Test T: The Reversing Lamps Are On Continuously
Refer to Wiring Diagram Set 93, Reversing Lamps for schematic and connector information Electrical Diagrams.
Normal Operation
The reversing lamps are illuminated, voltage is also provided to the Body Control Module (BCM), the auto-dimming interior rear view mirror and the Global Positioning System Module (GPSM) if equipped.
Automatic Transmission
The reversing lamps are provided voltage from the reversing lamps relay. Voltage is supplied to the reversing lamps relay when the ignition is in RUN. The Transmission Control Module (TCM) monitors the transmission gear status. When the TCM (Transmission Control Module) detects the transmission is in REVERSE (R), the TCM (Transmission Control Module) provides a ground for the reversing lamps relay coil. When the relay is energized, voltage is supplied to the reversing lamps.
Manual Transmission
Voltage is supplied to the reversing lamp switch when the ignition is in RUN. When the transmission is in REVERSE (R), the reversing lamp switch routes voltage to the reversing lamps.
- DTC C1137:24 (Reverse Gear Switch: Signal Stuck High)- A continuous and on-demand DTC that sets when the BCM (Body Control Module) detects a short to voltage from the reversing lamp voltage supply circuit.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Reversing lamps relay (automatic transmission)
- Reversing lamp switch (manual transmission)
- Auto-dimming interior rear view mirror
- BCM (Body Control Module)
- GPSM (Global Positioning System Module)
- TCM (Transmission Control Module) (automatic transmission)
PINPOINT TEST T : 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.
T1 DETERMINE THE TRANSMISSION TYPE
- Ignition OFF.
- Check the vehicle for a manual transmission.
Is the vehicle equipped with a manual transmission?
Yes
GO to T2.
No
GO to T3.
T2 CHECK THE REVERSING LAMP SWITCH
- Ignition OFF.
- Disconnect: Reversing Lamp Switch C169.
- Ignition ON.
Do the reversing lamps continue to illuminate?
Yes
If equipped with a GPSM (Global Positioning System Module), GO to T4.
If not equipped with a GPSM (Global Positioning System Module), GO to T5.
No
INSTALL a new reversing lamp switch. REFER to Reversing Lamp Switch Service and Repair. TEST the system for normal operation.
T3 CHECK THE REVERSING LAMPS RELAY OUTPUT
- Ignition OFF.
- Disconnect: Reversing Lamps Relay.
- Ignition ON.
Do the reversing lamps continue to illuminate?
Yes
If equipped with a GPSM (Global Positioning System Module), GO to T4.
If not equipped with a GPSM (Global Positioning System Module), GO to T5.
No
GO to T7.
T4 CHECK THE GPSM (Global Positioning System Module) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: GPSM (Global Positioning System Module) C2398.
- Ignition ON.
Do the reversing lamps continue to illuminate?
Yes
GO to T5.
No
GO to T10.
T5 CHECK THE BCM (Body Control Module) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: BCM (Body Control Module) C2280D.
- Ignition ON.
Do the reversing lamps continue to illuminate?
Yes
If equipped with an auto-dimming interior rear view mirror, GO to T6.
If not equipped with an auto-dimming interior rear view mirror, REPAIR circuit CET47 (BU) for a short to voltage. TEST the system for normal operation.
No
GO to T11.
T6 CHECK THE AUTO-DIMMING INTERIOR REAR VIEW MIRROR FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: Auto-Dimming Interior Rear View Mirror C911.
- Ignition ON.
Do the reversing lamps continue to illuminate?
Yes
REPAIR circuit CET47 (BU) for a short to voltage. TEST the system for normal operation.
No
INSTALL a new auto-dimming interior rear view mirror. TEST the system for normal operation.
T7 CHECK THE REVERSING LAMPS RELAY
- Ignition OFF.
- Substitute a known good relay.
- Ignition ON.
Do the reversing lamps continue to illuminate?
Yes
REMOVE the known good relay. GO to T8.
No
REMOVE the known good relay. INSTALL a new reversing lamps relay. TEST the system for normal operation.
T8 CHECK THE REVERSING LAMPS RELAY COIL GROUND CONTROLLED CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Connect: Reversing Lamps Relay.
- Disconnect: TCM (Transmission Control Module) C1750A.
- Ignition ON.
Do the reversing lamps continue to illuminate?
Yes
REPAIR circuit CLS28 (BU/WH) for a short to ground. TEST the system for normal operation.
No
GO to T9.
T9 CHECK THE TCM (Transmission Control Module) GEAR STATUS INPUT PID
- Ignition OFF.
- Connect: TCM (Transmission Control Module) C1750A.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: TCM (Transmission Control Module) DataLogger.
- Monitor the TCM (Transmission Control Module) gear status PID (GEAR_ENGAGED) while placing the gear selector lever through all its positions.
Does the PID agree with the gear selections?
Yes
GO to T12.
No
REFER to Automatically Shifted Manual Transmission/Transaxle to continue diagnosis of the gear input.
T10 CHECK FOR CORRECT GPSM (Global Positioning System Module) OPERATION
- Ignition OFF.
- Disconnect the GPSM (Global Positioning System Module) connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the GPSM (Global Positioning System Module) connector and make sure it seats correctly.
- Operate the system and verify the concern is still present.
Is the concern still present?
Yes
INSTALL a new GPSM (Global Positioning System 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.
T11 CHECK FOR CORRECT BCM (Body Control Module) OPERATION
- Ignition OFF.
- 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.
T12 CHECK FOR CORRECT TCM (Transmission Control Module) OPERATION
- Ignition OFF.
- Disconnect all the TCM (Transmission Control Module) connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the TCM (Transmission 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 TCM (Transmission 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.