Engine Speed Sensors
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 1993 Audi 90, 1993 Audi 100, 1992 Audi 100, 1991 Audi 90, and 1991 Audi 80. However, it is still accessible from the selected car via links, so may be relevant.
- 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 | |
NOTE:
Terminal identifications for Hall Effect sending unit are located on connector.