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.
2002 Audi S4 Quattro, AutomaticFACTORY OEM SERVICE PROCEDURE
Misfire Recognition: 3.0L
- Turn ignition off. Connect scan tool to Data Link Connector (DLC). DLC is located under cover on left side of instrument panel. See COMPONENT LOCATIONSΒ . Start engine. On scan tool, press "01" to select address word 01 - ENGINE ELECTRONICS. Press "Q" button to confirm input. Press "08" to select diagnostic function 08 - READ MEASURING VALUE BLOCK. Press "Q" button to confirm input, and go to next step.
- On scan tool, press "014" to select DISPLAY GROUP 014. Observe misfire recognition in display field No. 3. See Fig 1 . If displayed value is between zero and 5, go to next step. If displayed value is more than 5, go to step Β 5 .
- On scan tool press "FORWARD ARROW" or enter "015" to select DISPLAY GROUP 015. Observe misfire recognition in display fields No. 1, 2 and 3. See Fig 2 . If displayed value is zero, go to next step. If displayed value is more than zero, go to step Β 5 .
- On scan tool press "FORWARD ARROW" or enter "016" to select DISPLAY GROUP 016. Observe misfire recognition in display fields No. 1, 2 and 3. See Fig 3 . If specified value is more than zero, go to next step. If displayed value is zero, go to step Β 6 .
- If displayed value is more than specified, perform following tests:
- Check spark plugs.
- Check spark plug connector between ignition coil and spark plug. Check for cracks or tears in connector.
- Check ignition coil and power output stage. For diagnostic procedure, see ignition coil related DTCs under DIAGNOSTIC TROUBLE CODE DEFINITIONS in appropriate SELF-DIAGNOSTICS article.
- Check fuel injectors. See FUEL INJECTOR TESTΒ under FUEL SYSTEM.
- Check for un-metered air (vacuum leaks), or leaking crankcase ventilation system. Check for disconnected, torn, broken, loose or oil fouled vacuum hoses and pipes.
- Check compression. See PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES article.
- Using scan tool, clear DTCs and generate a ECM readiness code. See FUNCTION 05 - CLEARING DIAGNOSTIC TROUBLE CODES and READINESS CODE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article. Test drive vehicle. Using scan tool, retrieve DTCs. If DTC does not reset, testing is complete.
Factory Service Tools
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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.
