Pinpoint Test R: Both Reversing Lamps Are Inoperative
Reversing Lamps
Pinpoint Test R: Both Reversing Lamps Are Inoperative
Refer to Wiring Diagram Set 93, Reversing Lamps for schematic and connector information Electrical Diagrams.
Normal Operation - 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.
NOTE: The reversing lamps on 4-door vehicles share the same ground circuit.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Reversing lamps relay (automatic transmission)
- Reversing lamp switch (manual transmission)
- TCM (Transmission Control Module) (automatic transmission)
PINPOINT TEST R : BOTH 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.
R1 DETERMINE THE TRANSMISSION TYPE
- Ignition OFF.
- Check the vehicle for a manual transmission.
Is the vehicle equipped with a manual transmission?
Yes
VERIFY the CJB (Central Junction Box) fuse 6 (10A) is OK. If OK, GO to R2. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short Electrical Diagrams.
No
VERIFY the CJB (Central Junction Box) fuse 6 (10A) is OK. If OK, GO to R4. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short Electrical Diagrams.
R2 CHECK FOR VOLTAGE TO THE REVERSING LAMP SWITCH
- Disconnect: Reversing Lamp Switch C169.
- Ignition ON.
- Measure the voltage between the reversing lamp switch C169-1, circuit CBP06 (WH/BU), harness side and ground.
Is the voltage greater than 10 volts?
Yes
GO to R3.
No
REPAIR circuit CBP06 (WH/BU) for an open. TEST the system for normal operation.
R3 BYPASS THE REVERSING LAMP SWITCH
- Connect a fused jumper wire between the reversing lamp switch C169-1, circuit CBP06 (WH/BU), harness side and the reversing lamp switch C169-2, circuit CET47 (BU), harness side.
Do the reversing lamps illuminate?
Yes
REMOVE the jumper wire. INSTALL a new reversing lamp switch. REFER to Reversing Lamp Switch Service and Repair. TEST the system for normal operation.
No
For 4-door vehicles, LEAVE the jumper wire connected. GO to R7.
For 5-door vehicles, REMOVE the jumper wire. REPAIR circuit CET47 (BU) for an open. TEST the system for normal operation.
R4 CHECK THE REVERSING LAMPS RELAY
- Disconnect: Reversing Lamps Relay.
- Ignition ON.
- Substitute a known good relay and recheck the reversing lamps operation.
Do the reversing lamps operate correctly?
Yes
REMOVE the known good relay. INSTALL a new reversing lamps relay. TEST the system for normal operation.
No
REMOVE the known good relay. GO to R5.
R5 CHECK FOR VOLTAGE TO THE REVERSING LAMPS RELAY
- Ignition ON.
- Measure the voltage between the reversing lamps relay pin 1, circuit CBP06 (WH/BU), BJB (Battery Junction Box) face side and ground; and between the reversing lamps relay pin 3, circuit CBP06 (WH/BU), BJB (Battery Junction Box) face side and ground.
Are the voltages greater than 10 volts?
Yes
GO to R6.
No
REPAIR circuit CBP06 (WH/BU) for an open. TEST the system for normal operation.
R6 BYPASS THE REVERSING LAMPS RELAY
- Connect a fused jumper wire between the reversing lamps relay pin 3, circuit CBP06 (WH/BU), BJB (Battery Junction Box) face side and the reversing lamps relay pin 5, circuit CET47 (BU), BJB (Battery Junction Box) face side.
Do the reversing lamps illuminate?
Yes
REMOVE the jumper wire. GO to R8.
No
For 4-door vehicles, LEAVE the jumper wire connected. GO to R7.
For 5-door vehicles, REMOVE the jumper wire. REPAIR circuit CET47 (BU) for an open. TEST the system for normal operation.
R7 CHECK FOR VOLTAGE TO THE LH REVERSING LAMP
- Ignition OFF.
- Disconnect: LH Reverse Lamp C487.
- Ignition ON.
- Measure the voltage between the LH reversing lamp C487-1, circuit CET47 (BU), harness side and ground.
Is the voltage greater than 10 volts?
Yes
REMOVE the jumper wire. REPAIR circuit GD143 (BK/VT) for an open. TEST the system for normal operation.
No
REMOVE the jumper wire. REPAIR circuit CET47 (BU) for an open. TEST the system for normal operation.
R8 CHECK THE REVERSING LAMPS RELAY COIL GROUND CONTROLLED CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: TCM (Transmission Control Module) C1750A.
- Ignition ON.
- Measure the voltage between the reversing lamps relay pin 2, circuit CLS28 (BU/WH), BJB (Battery Junction Box) face side and ground.
Is any voltage present?
Yes
REPAIR circuit CLS28 (BU/WH) for a short to voltage. TEST the system for normal operation.
No
GO to R9.
R9 CHECK THE REVERSING LAMPS RELAY COIL GROUND CONTROLLED CIRCUIT FOR AN OPEN
- Ignition OFF.
- Connect: Reversing Lamps Relay.
- Ignition ON.
- Measure the voltage between the TCM (Transmission Control Module) C1750A-40, circuit CLS28 (BU/WH), harness side and ground.
Is the voltage greater than 10 volts?
Yes
GO to R10.
No
REPAIR circuit CLS28 (BU/WH) for an open. TEST the system for normal operation.
R10 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 R11.
No
REFER to Automatically Shifted Manual Transmission/Transaxle to continue diagnosis of the gear input.
R11 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.