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.
Notes
A/C Compressor-On-Signal & A/C Compressor Cut-Out, Checking: Notes — 1994 Audi S4 Service Manual & Component Testing >> Miscellaneous Controls >> A/C Compressor-On-Signal & A/C Compressor Cut-Out, Checking >> Notes A/C Compressor-On-Signal & A/C Compressor Cut-Out, Checking: Notes NOTE: The A/C compressor ON signal increases the basic value for the Idle Air Control (IAC) valve, ensuring that the IAC valve remains in the center range of the control map. The A/C compressor cut-out signal switches OFF the A/C compressor for approximately 12 seconds, when the vehicle is accelerated from a standing start or a low speed. NOTE: For location of ECM and harness connection. See COMPONENT LOCATIONS.
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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.