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.
Testing
Idle Speed: Testing — 1994 Audi S4 Service Manual & Component Testing >> Idle Control Systems >> Idle Speed >> Testing Idle Speed: Testing NOTE: DO NOT take measurements while radiator cooling fan is operating. Start engine and let idle. Select engine Basic Setting. See BASIC SETTING FUNCTION (4) in SELF-DIAGNOSTICS. Value in display channel 1 (display field, RPM) must be within 770-830 range. If NO: Perform the following steps: Read DTC Memory again. Initiate Output Diagnostic Test Mode (DTM). See OUTPUT DIAGNOSTIC TEST MODE in SELF-DIAGNOSTICS. Check test table for possible cause of malfunction. See BASIC SETTING VALUES CHECKING TABLES under OUTPUT DIAGNOSTIC TEST MODE in SELF-DIAGNOSTICS. Make the necessary repairs.
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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.