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.
- Turn the ignition on.
- With the scan tool, read DTCs
Does the scan tool display this DTC as active?
Yes
- Go To 2.
No
- Test complete, the condition or conditions that originally set this DTC are not present at this time. Using the 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.
- (A929) FUSED B+ CIRCUIT OPEN OR SHORTED TO GROUND
- Turn the ignition off.
- Disconnect the Multifunction Switch (SCM C2) harness connector.
- Measure the voltage of the (A929) Fused B+ circuit at the Multifunction Switch (SCM C2) harness connector.
Is battery voltage present?
Yes
- Go To 3.
No
- Repair the open in the (A929) Fused B+ circuit. Inspect the related fuse. If the fuse is open, check the circuit for a short to ground.
- Refer to STANDARD PROCEDURE and perform the BODY VERIFICATION TEST.
- (F944) RUN/START RELAY OUTPUT CIRCUIT OPEN OR SHORTED TO GROUND
- Turn the ignition on.
- Measure the voltage of the (F944) Run/Start Relay Output circuit at the Multifunction Switch (SCM C2) harness connector.
Is battery voltage present?
Yes
- Go To 4.
No
- Repair the open in the (F944) Fused Run/Start Relay Output circuit. Inspect the related fuse. If the fuse is open, check the circuit for a short to ground.
- Refer to STANDARD PROCEDURE and perform the BODY VERIFICATION TEST.
- (Z926) GROUND CIRCUIT OPEN
- Turn the ignition off.
- Measure the resistance between ground and the (Z926) Ground circuit at the Multifunction Switch (SCM C2) harness connector.
Is the resistance below 5.0 Ohms?
Yes
- Go To 5.
No
- Repair the open in the (Z926) Ground circuit.
- Refer to STANDARD PROCEDURE and perform the BODY VERIFICATION TEST.
- (D506) LIN BUS CIRCUIT OPEN OR SHORTED TO GROUND
- Turn the ignition on.
- Measure the voltage of the (D506) LIN Bus circuit at the Multifunction Switch (SCM C2) harness connector.
Is voltage present?
Yes
- Replace the Multifunction Switch in accordance with the Service Information. Refer to SWITCH, MULTIFUNCTION, REMOVAL .
- Refer to STANDARD PROCEDURE and perform the BODY VERIFICATION TEST.
No
- Repair the open in the (D506) LIN Bus circuit between the Multifunction Switch (SCM C2) and SCM C4 harness connectors.
- Refer to STANDARD PROCEDURE and perform the 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.