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 MANUALSJEEP2009COMMANDER LIMITED, 4.7 P, 4WDREPAIR AND DIAGNOSISELECTRICALHORNSFRONT CONTROL MODULE (FCM) - ELECTRICAL DIAGNOSTICSDTC TROUBLESHOOTINGB1648-REAR RIGHT TURN CONTROL CIRCUIT HIGHDIAGNOSTIC TEST

2009 Jeep Commander Limited, 4.7 P, 4WD

Diagnostic Test

2009 Jeep Commander Limited, 4.7 P, 4WDSECTION Diagnostic Test

TEST FOR INTERMITTENT CONDITION
1. Turn the ignition on.
2. Clear all FCM DTC's.
3. Turn the Right Turn Signal on.
4. With the scan tool, read DTC's.
  Does the scan tool read: B1648-REAR RIGHT TURN CONTROL CIRCUIT HIGH?
  
  Yes
  - Go to step 2
  No
  - The conditions that caused this code to set are not present at this time. Using the SYSTEM WIRING DIAGRAMS as a guide, inspect the wiring and connectors.
  - Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
RIGHT REAR TURN SIGNAL BULB
1. Turn the ignition off.
2. Inspect the Right Rear Turn Signal Bulb Assembly.
  Is the inoperative bulb OK?
  
  Yes
  - Go to step 3
  No
  - Replace the Inoperative bulb in accordance with the service information.
  - Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
(L62) RIGHT REAR TURN SIGNAL CONTROL CIRCUIT

Fig 1: Checking Right Rear Turn Signal Control Circuit
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the IPM C2 connector.
3. Disconnect the Right Rear Tail Lamp assembly.
4. Measure the resistance of the (L62) Right Rear Turn Signal Control circuit.
  Is the resistance above 5.0 ohms?
  
  Yes
  - Repair the (L62) Right Rear Turn Signal Control circuit for an open.
  - Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
  No
  - Go to step 4
FRONT CONTROL MODULE

Fig 2: Checking Front Control Module
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the Front Control Module from the IPM 49-way connector.
3. Measure the voltage between (L62) Right Rear Turn Signal Control circuit and ground in the PDC.
  Is there any voltage present?
  
  Yes
  - Replace the Power Distribution Center.
  - Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
  No
  - Replace the Front Control Module.
  - Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .

RENDER: 1.0x

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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.