Pinpoint Test U: Both Reversing Lamps Are Inoperative
Reversing Lamps
Pinpoint Tests
Pinpoint Test U: Both Reversing Lamps Are Inoperative
Refer to Wiring Diagram Set 93, Reversing Lamps for schematic and connector information. Diagrams By Number
Normal Operation
When the ignition switch is in the RUN position, voltage is provided to the digital Transmission Range (TR) sensor from the Central Junction Box (CJB). When the transmission is placed in REVERSE (R), the digital TR sensor routes voltage to the reversing lamps. The reversing lamps share a ground with the license plate lamps.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Digital TR sensor
PINPOINT TEST U: 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.
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U1 CHECK THE REVERSING LAMPS GROUND CIRCUIT FOR AN OPEN
- Ignition OFF.
- Place the headlamp switch in the PARKING LAMPS ON position and observe the license plate lamps.
- Do the license plate lamps illuminate?
Yes
GO to U2.
No
REPAIR circuit 57 for an open. TEST the system for normal operation.
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U2 CHECK THE DIGITAL TR SENSOR ADJUSTMENT
WARNING: If the vehicle is equipped with a fire suppression system, repower the system. For important safety warnings and procedures, refer to Fire Suppression System. Failure to follow these instructions may result in serious personal injury. Description and Operation
- Place the headlamp switch in the OFF position.
- If equipped with a fire suppression system, depower the system. Refer to Fire Suppression System Procedures.
- Check the digital TR sensor adjustment. Refer to Automatic Transaxle/Transmission - 4R70E/4R75E 4R70E/4R75E.
- Is the digital TR sensor adjusted correctly?
Yes
GO to U3.
No
ADJUST the digital TR sensor. REFER to Automatic Transaxle/Transmission - 4R70E/4R75E 4R70E/4R75E. TEST the system for normal operation. If equipped with a fire suppression system, REPOWER the system. REFER to Fire Suppression System Procedures.
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U3 CHECK FOR VOLTAGE TO THE DIGITAL TR SENSOR
- Disconnect: Digital TR Sensor C167.
- Connect: Negative Battery Cable.
- Ignition ON.
- Measure the voltage between the digital TR sensor C167-9, circuit 1789 (VT/WH), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to U4.
No
VERIFY the CJB fuse 20 (10A) is OK. If OK, REPAIR circuit 1789 (VT/WH) for an open. TEST the system for normal operation. If equipped with a fire suppression system, REPOWER the system. REFER to Fire Suppression System Procedures. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. Diagrams By Number
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U4 BYPASS THE DIGITAL TR SENSOR
- Ignition OFF.
- Connect a fused jumper wire between the digital TR sensor C167-9, circuit 1789 (VT/WH), harness side and the digital TR sensor C167-11, circuit 140 (BK/PK), harness side.
- Ignition ON.
- Do the reversing lamps illuminate?
Yes
REMOVE the jumper wire. INSTALL a new digital TR sensor. REFER to Automatic Transaxle/Transmission - 4R70E/4R75E Service and Repair. TEST the system for normal operation. If equipped with a fire suppression system, REPOWER the system. REFER to Fire Suppression System Procedures.
No
REMOVE the jumper wire. REPAIR circuit 140 (BK/PK) for an open. TEST the system for normal operation. If equipped with a fire suppression system, REPOWER the system. REFER to Fire Suppression System Procedures.
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