With Manufacturer's Scan Tool

ENGINE SPEED SENSOR, CHECKING

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

Special tools and equipment
- Test box VAG 1598/22 (through my 1999)
- Test box VAG 1598/31 (from my 2000)
- Digital multimeter US1119 (Fluke 83 or equivalent)
- Adapter set VAG 1594
- Wiring diagram

Test sequence






- Separate gray 3-pin connector (arrow) to engine speed sensor.






- Measure resistance between connector terminals 1 + 2.
- Specification: 1.0 to 1.5 k ohms

If the specification is not obtained:
- Replace engine speed sensor -G28-, refer to item 19, Component Locations, Overview
- Check DTC memory and, if necessary, repair any malfunctions and then erase DTC memory, refer to "Diagnostic Trouble Code (DTC) Memory, Checking and Erasing" Testing and Inspection
- Read readiness code.

If the DTC memory has been erased or the engine control module was disconnected from permanent battery positive (B+), the readiness code must be generated again.

If the specification is obtained:
- Remove wiper arms and plenum cover:






- Connect test box VAG 1598/22 (through my 1999) or VAG 1598/31 (from my 2000) to control module wiring harness.










- Check wiring between test box and 3 pin connector for open circuit according to wiring diagram.
- Wire resistance: max. 1.5 ohms
- Check wires at 3 pin connector for short circuit to one another according to wiring diagram.
- Specification: Infinity ohms

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

If no malfunction is detected:
- Replace engine control module.