Test sequence

NOTE: The engine speed sensor is a combined speed sensor and reference mark sensor. The engine cannot be started without a signal from the Engine speed (RPM) sensor -G28-. If the signal from the Engine speed (RPM) sensor -G28- fails while the engine is running, the engine will cut out immediately.

Before performing test, make sure that sensor is correctly installed and firmly seated.
Disconnect connector to engine speed sensor. See IDENTIFICATION OF CONNECTOR BRACKET - LEFT SIDE OF VEHICLE .
Connect multimeter between terminals 2 and 3 to measure resistance.

Fig 1: Identifying Engine Speed Sensor Terminals
Courtesy of AUDI OF AMERICA, INC.
- Specified value: 730 to 1000 Ω
NOTE: The resistance value of the engine speed sensor is associated with a temperature of 20 °C. The resistance increases if the temperature increases.

If specified value is not attained:
Install a new engine speed sensor.
If specified value is attained:
Connect multimeter between terminals 2 and 1 (screen) and 3 and 1 (screen) to measure resistance.

Fig 2: Identifying Engine Speed Sensor Terminals
Courtesy of AUDI OF AMERICA, INC.
- Specified value: each case INFINITY Ω (no continuity)
If specified value is not attained:
Install a new engine speed sensor.
If specified value is attained:
Connect test box VAG1598/31 to wiring harness for engine control module; do not connect engine control module. See WIRING AND COMPONENT CHECK WITH TEST BOX VAG 1598/31 .

Check for open circuit and short to positive or ground in following wiring connections:

Fig 3: Identifying Engine Speed Sensor Harness Connector Terminals

Courtesy of AUDI OF AMERICA, INC.

CONNECTOR TERMINAL 1, 2, 3 & SOCKET 108, 90, 82 (ENGINE SPEED SENSOR)

Connector terminal	Test box VAG1598/31 Socket
1 (screening)	108
2 (ground)	90
3 (signal)	82

Repair any open/short circuit as necessary.
If no wiring malfunction is detected:
Replace engine control module. See ENGINE CONTROL MODULE (ECM) (WITHOUT METAL ANTI-THEFT HOUSING), REPLACING .