Turn ignition off. Connect VAS 5051 or equivalent scan tool to Data Link Connector (DLC). DLC is located under cover on left side of instrument panel. Start engine. On scan tool from selection 1 select diagnostic function 08 - READ MEASURING VALUE BLOCK. From button field 2, enter 014 to select DISPLAY GROUP 014, press "Q" button to confirm input, and go to next step.
On scan tool observe misfire recognition in display fields No. 3 and 4. See Fig 1 . If displayed value is not obtained, go to next step. If displayed value is obtained, go to step 4 .
If displayed value is 0-5, perform following tests:
- Check spark plugs. Replace as necessary.
- Check spark plug connector between ignition coil and spark plug. Maximum resistance in connector is 2000 ohms. Check for cracks or tears in connector.
- Check ignition coil and power output stage. For diagnostic procedure, see DIAGNOSTIC TROUBLE CODE DEFINITIONS in appropriate SELF-DIAGNOSTICS article.
- Check fuel injectors. See FUEL INJECTOR TEST under FUEL SYSTEM.
If problem is found, repair as necessary. After repair go to next step.
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.

Fig 1: Display Group 014: Misfire Recognition (4.2L)

Courtesy of AUDI OF AMERICA, INC.

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.

Safety Warning

Misfire Recognition: 4.2L