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.
2012 Buick Regal BaseFACTORY OEM SERVICE PROCEDURE
Circuit/System Testing
- Use the schematic to identify the following:
- Control module and LIN device locations on the serial data circuit.
- The control module serial data circuit terminals and the LIN device B+, ignition, ground, and serial data circuit terminals.
- A loss of serial data communications DTC does not represent a failure of the master control module that set it.
- Ignition OFF, disconnect the harness connector at the S56 radio control multifunction switch.
- Test for less than 10 Ξ© between ground circuit and ground.
- If greater than the specified range, test the ground circuit for an open/high resistance.
- Ignition ON, verify that a test lamp illuminates between B+ circuit and ground.
- If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the S56 radio control multifunction switch.
- Test for 2-12 V between the serial data circuit and ground.
- If greater than the specified range, test the serial data circuit for a short to voltage. If the circuit tests normal, replace the A22 radio controls.
- If less than the specified range, test the serial data circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the A22 radio controls.
- If all circuits test normal, replace the S56 radio control multifunction switch.
NOTE:
Factory Service Tools
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:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.