With Manufacturer's Scan Tool

Engine Speed (RPM) Sensor, Checking

The engine speed sensor -G28- is a speed and reference mark sensor. The engine will not start if there is no speed signal. If the speed signal fails when the engine is running, it will cause the engine to stall immediately.

Special tools, test equipment and auxiliary items
- Test box V.A.G 1598/31
- Multimeter (Fluke 83 or equivalent)
- Adapter set V.A.G 1594
- Wiring diagram

Test sequence
- Separate grey 3-pin connector -arrow- to engine speed sensor.






- Measure sensor resistance between contacts 2 + 3 of connector to sensor.
Specification: 730 - 1000 Ohms

- Check the sensor for short between contacts 1 + 2 as well as 1 + 3
Specification: Infinity Ohms

If the specifications are not obtained:
- Replace engine speed sensor -G28-, item 8.
- Check DTC memory, if necessary, repair any malfunctions and then erase DTC memory.
- Read-out the readiness code. If the DTC memory has been erased or the engine control module was disconnected from permanent positive, the readiness code must be generated again.

If no sensor malfunction is detected:
- Remove inner plenum chamber cover, left:






- Connect test box V.A.G 1598/31 to control module wiring harness. The engine control module is not connected by this action.






- Check wiring for open circuit between test box and 3-pin connector using wiring diagram.
- Contact 1 + socket 108
- Contact 2 + socket 90
- Contact 3 + socket 82
Wire resistance: Max. 1.5 Ohms

- Additionally check wires for short to one another.

If no wiring problem is detected:
- Remove sensor and check sensor wheel for secure fit, damage and run-out.

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

If no malfunction is detected on sensor wheel:
- Replace Engine Control Module (ECM).