Pinpoint Test T: Both Reversing Lamps Are Inoperative
Reversing Lamps
Pinpoint Tests
Pinpoint Test T: Both Reversing Lamps Are Inoperative
Refer to Wiring Diagram Set 93, Reversing Lamps for schematic and connector information. Diagrams By Number
Normal Operation
The Smart Junction Box (SJB) receives the transmission gear status from the PCM (5R55S transmission) or the Transmission Control Module (TCM) (6R60 transmission) through the Instrument Cluster (IC) gateway, over the communication network. When the transmission is placed in REVERSE (R), the PCM sends a message over the communication network indicating the transmission is in reverse. The SJB then provides ground to an internal relay, which routes voltage to the reversing lamps.
The PCM or TCM sets DTCs if there are any concerns with the input from the Transmission Range (TR) sensor.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- SJB
PINPOINT TEST T: 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.
NOTE: Make sure the stoplamps operate correctly before continuing diagnostics.
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T1 CARRY OUT THE PCM OR TCM SELF-TEST
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: PCM or TCM Self-Test.
- Carry out the PCM (5R55S transmission) or the TCM (6R60 transmission) self-test.
- Are any PCM or TCM TR sensor DTCs present?
Yes
REFER to Automatic Transmission/Transaxle &/or Transmission Control Systems.
No
GO to T2.
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T2 RETRIEVE THE RESULTS FROM THE SJB SELF-TEST
- Review the recorded results from the SJB self-test.
- Are any DTCs present?
Yes
REFER to Body Control Systems.
No
VERIFY the SJB fuse 15 (10A) is OK. If OK, GO to T3. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. Diagrams By Number
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T3 CHECK THE SJB REVERSE LAMP OUTPUT CIRCUIT FOR AN OPEN
- Disconnect: LH Reversing Lamp.
- Disconnect: SJB C2280a.
- For Explorer, measure the resistance between the LH reversing lamp C487-2, circuit CBP15 (BN/BU), harness side and the SJB C2280a-6, circuit CBP15 (BN/BU), harness side.
- For Mountaineer, measure the resistance between the LH reversing lamp C487-1, circuit CBP15 (BN/BU), harness side and the SJB C2280a-6, circuit CBP15 (BN/BU), harness side.
- For Explorer Sport Trac, measure the resistance between the LH reversing lamp C451-3, circuit CBP15 (BN/BU), harness side and the SJB C2280a-6, circuit CBP15 (BN/BU), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to T4.
No
REPAIR circuit CBP15 (BN/BU) for an open. CLEAR the DTC. REPEAT the self-test.
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T4 CHECK FOR CORRECT SJB OPERATION
- 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. REFER to Body Control Systems. 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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