Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

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HOMESERVICE MANUALSJEEP2010GRAND CHEROKEE LIMITED, 5.7 T, 4WDREPAIR AND DIAGNOSISENGINE PERFORMANCETUNE-UP(FRONT CONTROL MODULE (FCM) - ELECTRICAL DIAGNOSTICS)DTC TROUBLESHOOTINGB1667-REVERSE LAMP CONTROL CIRCUIT LOWDIAGNOSTIC TEST

2010 Jeep Grand Cherokee Limited, 5.7 T, 4WD

Diagnostic Test

2010 Jeep Grand Cherokee Limited, 5.7 T, 4WDSECTION Diagnostic Test

INTERMITTENT CONDITION
1. Turn the ignition on.
2. With the scan tool, clear all FCM DTCs.
3. Shift the transmission into reverse.
4. With the scan tool, read DTCs.
  Does the scan tool display: B1667-REVERSE LAMP CONTROL CIRCUIT LOW?
  
  Yes
  - Go to step 2
  No
  - The condition that caused the symptom is currently not present. Inspect the related wiring for a possible intermittent condition. Look for any chafed, pierced, pinched, or partially broken wires.
  - Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
CHECK THE (L1) BACK-UP LAMP FEED CIRCUIT FOR A SHORT IN THE HARNESS

Fig 1: Checking Back-Up Lamp Circuits For Short
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the IPM C2 harness connector.
3. Measure the resistance between ground and the (L1) Back-up Lamp circuits.
  Are the resistances below 5.0 Ohms?
  
  Yes
  - Repair the short to ground in the appropriate (L1) Back-up Lamp circuit.
  - Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
  No
  - Go to step 3
CHECK (L1) BACK-UP LAMP FEED CIRCUIT IN IPM FOR A SHORT TO GROUND

Fig 2: Identifying Back-Up Lamp Circuit Connector Terminal At IPM 49-Way Connector
Courtesy of CHRYSLER LLC
1. Disconnect the Front Control Module (FCM) from the IPM 49-way connector.
2. Reconnect the IPM C2 harness connector.
3. Measure the resistance of the (L1) Back-up Lamp circuit between ground and the IPM 49-way connector.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Replace the Integrated Power Module (IPM) in accordance with the Service Information.
  - Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
  No
  - Replace the Front Control Module (FCM) in accordance with the Service Information.
  - Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.