Engine Speed Sensor: Testing and Inspection

Engine Speed (RPM) Sensor -G28-, Checking

Test requirements
- Correct installation and secure seating of Engine Speed (RPM) Sensor.
- No shavings or damage at Engine Speed (RPM) Sensor or sensor wheel.






- Disconnect gray harness connector of Engine Speed (RPM) Sensor -G28- (connector strip on underside of transmission, position 1).






- Use adapter cables from V.A.G 1594 connector test kit to connect V.A.G 1526 portable multimeter to terminals 2 and 3 for resistance measurement.
Specified value: approx. 450 to 1200 Ohms

If specified value is not obtained, replace Engine Speed (RPM) Sensor.

- If specified value is obtained, connect portable multimeter to terminal 1 and 2 as well as terminal 1 and 3.
Specified value: infinite Ohms respectively (no continuity).

If specified value is not obtained, replace Engine Speed (RPM) Sensor.
- Read readiness code. If DTC memory was erased, readiness code must be generated again.

If specified values are obtained, check wire connections between harness connector and Engine Control Module (ECM) as follows:
- Connect V.A.G 1598/31 test box to wiring harness of Engine Control Module (ECM)

The following wire connections must be checked for short circuit to B+, Ground (GND) and for open circuit






Terminal at sensor coupling V.A.G 1598/31 test box or
Engine Control Module (ECM)
1 108
2 90
3 82

- Repair open circuit in wiring or short circuit if necessary.

- Check all wires for short circuit to each other.
Specified value: Infinity Ohms (no continuity)

If no malfunction is found in wires:
- Remove Engine Speed (RPM) Sensor and check sensor wheel for proper seating, damage and run-out.

NOTE: There is a larger-sized gap on the sensor wheel. This gap is the reference mark and does not mean that the sensor wheel is damaged.

If nothing seems to be wrong with the sensor wheel:
- Replace Engine Control Module (ECM)
- Read readiness code. If DTC memory was erased, readiness code must be generated again