Pinpoint Test V: The Reversing Lamps Are On Continuously
Reversing Lamps
Pinpoint Tests
Pinpoint Test V: The Reversing Lamps Are On Continuously
Refer to Wiring Diagram Set 93, Reversing Lamps for schematic and connector information. Diagrams By Number
Normal Operation - Manual Transmission
The PCM sends a voltage reference signal to the reversing lamp switch through circuit 1789 (VT/WH). When the transmission is placed in REVERSE (R), the reversing lamp switch closes and routes the signal back to the PCM through circuit 359 (GY/RD). The PCM then sends a message to the Smart Junction Box (SJB), through the Instrument Cluster (IC) gateway function, over the communication network. The SJB then provides voltage through circuits 1362 (DG/OG) and 1367 (WH/YE) to the LH and RH reversing lamps.
Automatic Transmission
When the PCM detects the transmission is in REVERSE (R), a message to the Smart Junction Box (SJB), through the IC gateway function, over the communication network. The SJB then provides voltage through circuits 1362 (DG/OG) and 1367 (WH/YE) to the LH and RH reversing lamps.
The PCM sets DTCs if any faults with the digital Transmission Range (TR) sensor inputs are detected.
- DTC B2525 (Left Rear Backup Lamp Circuit Failure) - a continuous and on-demand DTC that sets when the SJB detects a short to voltage on the LH reversing lamp voltage supply circuit.
- DTC B2532 (Right Rear Backup Lamp Circuit Short to Battery) - a continuous and on-demand DTC that sets when the SJB detects a short to voltage on the RH reversing lamp voltage supply circuit.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Reversing lamp switch (manual transmission)
- Digital TR sensor input (automatic transmission) concern
- SJB
- PCM
PINPOINT TEST V: 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.
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V1 RETRIEVE THE RECORDED DTCs FROM THE SJB SELF-TEST
- Ignition OFF.
- Retrieve the recorded results from the SJB self-test.
- Was DTC B2525 or B2532 present?
Yes
GO to V2.
No
GO to V3.
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V2 CHECK CIRCUITS 1362 (DG/OG) AND 1367 (WH/YE) FOR A SHORT TO VOLTAGE
- Disconnect: SJB C2280d.
- Ignition ON.
- Does either reversing lamp continue to illuminate?
Yes
REPAIR circuit 1362 (DG/OG) (LH reversing lamp) or circuit 1367 (WH/YE) (RH reversing lamp) as necessary. CLEAR the DTCs. REPEAT the self-test.
No
GO to V6.
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V3 CHECK THE PCM
- Disconnect: PCM C175t.
- Ignition ON.
- Do the reversing lamps continue to illuminate?
Yes
GO to V6.
No
If equipped with a manual transmission, GO to V4.
If equipped with an automatic transmission, REFER to Transmission Control Systems to continue diagnosis of the digital TR sensor. Testing and Inspection
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V4 CHECK THE REVERSING LAMP SWITCH
- Ignition OFF.
- Connect: PCM C175t.
- Disconnect: Reversing Lamp Switch C169.
- Ignition ON.
- Do the reversing lamps continue to illuminate?
Yes
GO to V5.
No
INSTALL a new reversing lamp switch. REFER to Reversing Lamp Switch Service and Repair. TEST the system for normal operation.
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V5 CHECK CIRCUIT 1789 (VT/WH) FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: PCM C175t.
- Measure the resistance between the reversing lamp switch C169-A, circuit 1789 (VT/WH), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to V7.
No
REPAIR the circuit. TEST the system for normal operation.
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V6 CHECK FOR CORRECT SJB OPERATION
- Ignition OFF.
- Disconnect all the SJB connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the SJB 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 SJB. 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.
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V7 CHECK FOR CORRECT PCM OPERATION
- Ignition OFF.
- 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.
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