Remove Gray (engine RPM) and Black (ignition timing reference) connectors from bracket near ignition coil. For each connector, check continuity between terminals No. 1 and No. 2. See Fig 2 . Ohmmeter reading should be 1000 ohms.
If reading is not 1000 ohms, replace sensor(s). If reading is 1000 ohms, check continuity between terminals No. 1 and No. 3, and terminals No. 2 and No. 3 of each connector. If ohmmeter indicates infinity, go to next step. If ohmmeter does not indicate infinity, replace sensor(s).
Unplug connector from ECU. Check wiring, on harness side of connectors, between each sensor and ECU. See ENGINE SPEED SENSOR CIRCUITS table. See Figure and Figure . Ensure resistance of each wire between ECU and sensor connectors is zero ohm.
Ensure clearance between ignition timing reference sensor and flywheel pin is .43" (1.10 mm). If engine speed sensors and wiring circuits are okay, replace ECU.

ENGINE SPEED SENSOR CIRCUITS

Sensor Harness Connector Pin		ECU Harness Connector Terminal
Gray (Engine RPM)
1		29
2		11
3		28
Black (Ignition Timing Reference)
1		13
2		12
3		28

Fig 1: ECU Harness Connector Terminal I.D. (2.2L)

Courtesy of AUDI OF AMERICA, INC.

Chapter Navigation

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

Engine Speed Sensors