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.
Diagnostic Test
- TEST FOR INTERMITTENT CONDITION
- Turn the ignition on.
- Clear all FCM DTC's.
- Turn the Right Turn Signal on.
- 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 wiring diagram/schematic 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
- Turn the ignition off.
- 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
- Turn the ignition off.
- Disconnect the IPM C2 connector.
- Disconnect the Right Rear Tail Lamp assembly.
- 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
- Turn the ignition off.
- Disconnect the Front Control Module from the IPM 49-way connector.
- 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 .
Use the Manual With the Right Hardware
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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.
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