Pinpoint Test Z: The Reversing Lamps Are On Continuously
Reversing Lamps
Pinpoint Tests
Pinpoint Test Z: The Reversing Lamps Are On Continuously
Refer to Wiring Diagram Set 93, Reversing Lamps for schematic and connector information. Diagrams By Number
Normal Operation
Voltage is supplied from the Battery Junction Box (BJB) fuse 26 (10A) to the reversing lamps relay coil. The reversing lamps relay switch side is supplied voltage by the Central Junction Box (CJB) fuse 138 (10A). The reversing lamps relay coil ground is controlled by the PCM. When the transaxle is in REVERSE (R), the PCM completes the ground, energizing the reversing lamps relay. When the reversing lamps relay is energized, voltage is routed to the reversing lamps, the Generic Electronic Module (GEM) and the Parking Aid Module (PAM) (if equipped).
The PCM sets digital Transmission Range (TR) sensor related DTCs if any concerns exist with inputs from the TR sensor.
- DTC B1810 (Lamp Backup Switch Input Circuit Failure) - an on-demand DTC that sets when the GEM detects a short to voltage from the reversing lamps voltage supply circuit.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Reversing lamps relay
- PAM
- GEM
- PCM
PINPOINT TEST Z: 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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Z1 CHECK FOR RECORDED PCM DTCs
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: PCM Self-Test.
- Carry out the PCM Key ON Engine OFF (KOEO) and Key ON Engine Running (KOER) self-tests.
- Are any DTCs present?
Yes
REFER to Computers and Control Systems.
No
GO to Z2.
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Z2 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 rear parking aid, GO to Z3. If not equipped with rear parking aid, GO to Z4.
No
GO to Z5.
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Z3 CHECK THE PAM
- Ignition OFF.
- Disconnect: PAM C2023.
- Ignition ON.
- Do the reversing lamps continue to illuminate?
Yes
GO to Z4.
No
GO to Z7.
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Z4 CHECK THE GEM
- Ignition OFF.
- Disconnect: GEM C201a.
- Ignition ON.
- Do the reversing lamps continue to illuminate?
Yes
REPAIR the reversing lamps voltage supply circuit for a short to voltage. TEST the system for normal operation.
No
GO to Z8.
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Z5 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 Z6.
No
REMOVE the known good relay. INSTALL a new reversing lamps relay. TEST the system for normal operation.
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Z6 CHECK THE PCM
- Ignition OFF.
- Connect: Reversing Lamps Relay.
- Disconnect: PCM C175t.
- Ignition ON.
- Do the reversing lamps continue to illuminate?
Yes
REPAIR circuit 31S-LG45 (BK/GN) for a short to ground. TEST the system for normal operation.
No
GO to Z9.
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Z7 CHECK FOR CORRECT PAM OPERATION
- Ignition OFF.
- Disconnect the PAM connector.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the PAM 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 PAM. REFER to Parking Aid Service and Repair. 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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Z8 CHECK FOR CORRECT GEM OPERATION
- Ignition OFF.
- Disconnect all the GEM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the GEM 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 GEM. REFER to Multifunction Electronic Modules Service and Repair. 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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Z9 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. REFER to Electronic Engine Controls Service and Repair. 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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