Pinpoint Test X: The Reversing Lamps Are On Continuously
Reversing Lamps
Pinpoint Tests
Pinpoint Test X: The Reversing Lamps Are On Continuously
Refer to Wiring Diagram Set 93, Reversing Lamps for schematic and connector information. Diagrams By Number
Normal Operation
The PCM monitors the transaxle gear status. When the PCM detects the transaxle in REVERSE (R), the PCM provides ground for the reversing lamps relay coil through circuit CLS28 (BU/WH).
Voltage is supplied from the Battery Junction Box (BJB) fuse 46 (15A) to the coil side of the reversing lamps relay and fuse 26 (20A) to the switched side of the reversing lamps relay. When the reversing lamps relay is energized, voltage is routed to the reversing lamps, the auto-dimming interior mirror, and the trailer tow reversing lamp fuse through circuit CLS10 (GN/BN).
- DTC P1910 (Reverse Lamp Control Circuit/Open) - sets when the PCM detects no voltage on the reversing lamp relay coil ground control circuit (if the coil ground control circuit is short to ground).
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Reversing lamps relay
- Auto-dimming interior mirror
- PCM
PINPOINT TEST X: 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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X1 CHECK FOR PCM TR SENSOR DTCs FROM THE SELF-TEST
- Review the DTCs from the PCM Key ON Engine OFF (KOEO) self-test.
- Are any TR sensor DTCs present?
Yes
Refer to Transmission Control Systems. Testing and Inspection
No
GO to X2.
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X2 CHECK THE REVERSING LAMPS RELAY OUTPUT
- Ignition OFF.
- Disconnect: Reversing Lamps Relay.
- Ignition ON.
- Do the reversing lamps continue to illuminate?
Yes
GO to X3.
No
GO to X6.
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X3 CHECK THE AUTO-DIMMING INTERIOR MIRROR FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: Auto-Dimming Interior Mirror C911 or C9012.
- Ignition ON.
- Do the reversing lamps continue to illuminate?
Yes
GO to X4.
No
INSTALL a new auto-dimming interior mirror. TEST the system for normal operation.
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X4 CHECK THE TRAILER TOW REVERSING LAMP CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: Auxiliary Relay Box Fuse 1 (10A).
- Ignition ON.
- Do the reversing lamps continue to illuminate?
Yes
GO to X5.
No
REPAIR circuit CAT03 (GN/BN) for a short to voltage. TEST the system for normal operation.
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X5 ISOLATE THE SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: BJB Fuse 36 (10A).
- Ignition ON.
- Do the reversing lamps continue to illuminate?
Yes
REPAIR circuit CLS10 (GN/BN) between the fuse and the reversing lamps. TEST the system for normal operation.
No
REPAIR circuit CLS10 (GN/BN) between the reversing lamps relay and AJB. TEST the system for normal operation.
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X6 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 X7.
No
REMOVE the known good relay. INSTALL a new reversing lamps relay. TEST the system for normal operation.
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X7 CHECK REVERSING LAMPS RELAY OUTPUT CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Connect: Reversing Lamps Relay.
- Disconnect: PCM C175t.
- Ignition ON.
- Do the reversing lamps continue to illuminate?
Yes
REPAIR circuit CLS28 (BU/WH) for a short to voltage. CLEAR the DTCs. REPEAT the self-test.
No
GO to X8.
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X8 CHECK FOR CORRECT PCM OPERATION
- Disconnect the PCM connector.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the PCM 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 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. CLEAR any DTCs. REPEAT the self-test.
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