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
- CHECK FOR AN ACTIVE DTC NOTE:
Before proceeding with the diagnostic procedure, verify that the connections are properly made, seated and verify proper pin terminal tension. A loose connection at any of the SCCM connectors may cause the DTC to set.
- With the scan tool, read Body Control Module (BCM) DTCs and record on the repair order.
- Record the Environmental Data.
- With the scan tool, erase DTCs.
- Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
- With the scan tool, read BCM DTCs.
Did the DTC return?
Yes
- Go To 2
No
- Test complete. The condition or conditions that originally set this DTC are not present at this time. Using the appropriate wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension.
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
- CHECK THE STEERING CONTROL MODULE (SCM) OPERATION
- Turn the ignition on.
- Using the scan tool, view the SCM Data while actuating the Left and Right Turn Lamps, High/Low Beams and Front Wiper/Washer functions on and off.
Does the SCM Data match the on and off states of the Left and Right Turn Lamps, High/Low Beams and Front Wiper/Washer functions?
Yes
- Replace the Steering Control Module (SCM) in accordance with the Service Information. Refer to MODULE, STEERING COLUMN (SCM), REMOVAL .
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
No
- Go To 3
- CHECK THE (D507) LIN BUS CIRCUIT FOR A SHORT TO VOLTAGE
- Turn the ignition off.
- Disconnect the SCM C1 harness connector.
- Turn the ignition on.
- Measure the voltage on the (D507) LIN Bus circuit at the SCM C1 harness connector.
Is the voltage greater than 10.0 volts?
Yes
- Repair the short to voltage on the (D507) LIN Bus circuit.
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
No
- Go To 4
- CHECK THE (D507) LIN BUS CIRCUIT FOR A SHORT TO GROUND
- Turn the ignition off.
- Disconnect the SCM C1, C2 and C3 connectors.
- Check for continuity between ground and the (D507) LIN Bus circuit at the SCM C1 harness connector.
Is there continuity between ground and the (D507) LIN Bus circuit?
Yes
- Repair the short to ground on the (D507) LIN Bus circuit.
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
No
- Go To 5
- CHECK THE (D507) LIN BUS CIRCUIT FOR AN OPEN
- Measure the resistance of the (D507) LIN Bus circuit between the SCM C1 harness connector and SCM C2 harness connector.
- Measure the resistance of the (D507) LIN Bus circuit between the SCM C1 harness connector and SCM C3 harness connector.
Is the resistance above 3.0 Ohms?
Yes
- Repair the open in the (D507) LIN Bus circuit.
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
No
- Replace the Multifunction Switch in accordance with the Service Information. Refer to SWITCH, MULTIFUNCTION, REMOVAL .
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
NO RELATED
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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.