With Manufacturer's Scan Tool

Engine Speed (RPM) Sensor -G28-, Checking







Special tools and workshop equipment required

- V.A.G 1526 A.
- V.A.G 1594 A.
- V.A.G 1598/31.

NOTE: The engine speed (RPM) 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.

Test sequence

- Before performing test, make sure that sensor is correctly installed and firmly seated.







- Disconnect engine speed (RPM) sensor connector -G28- -Pos. 3-.







NOTE: To gain access to the connector, remove coolant expansion tank bolt -arrow- and move expansion tank to the side. Fuel hoses remain connected.







- Connect multimeter between terminals 2 and 3 to measure resistance.
- Specified value: 730...1000 Ohm

NOTE: The resistance value of the engine speed (RPM) sensor -G28- is associated with a temperature of 20 degree C. The resistance increases if the temperature increases.

If specified value is not obtained:
- Install new engine speed (RPM) -G28-.

If specified value is obtained:







- Connect multimeter between terminals 2 and 1 -screen-and 3 and 1 -screen- to measure resistance.
- Specified value: each case infinite Ohm (no continuity).

If specified value is not obtained:
- Install a new Engine speed (RPM) sensor -G28-.

If specified value is obtained:

- Connect test box V.A.G 1598/31 to wiring harness for ECM; do not connect ECM.







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

Connector Test box VAG 1598/31
terminal Socket

1 (Screening) 108
2 (ground) 90
3 (signal) 82

- Repair any open/short circuit as necessary.

If no wiring problems are found:
- Replace ECM.