Engine Speed Sensor: Testing and Inspection

Engine speed (RPM) sensor -G28-, checking

The engine speed (RPM) sensor -G28- detects engine speed and reference marks. Without an engine speed signal, the engine will not start. If the engine speed signal fails while the engine is running, the engine will stop immediately.

Special tools and equipment
- VAG 1598/31 adapter cable
- VAG 1526 multimeter or VAG 1715 multimeter
- VAG 1594 connector test kit
- Wiring diagram

Test sequence

I - Engine code ATW
II - Engine codes AUG, AWM







- Disconnect gray 3-pin harness connector to engine speed (RPM) sensor (arrow).







- Measure resistance of sensor between terminals 2 + 3 of connector -1-. Specification: 400 to 1000 Ohms
- Check sensor for short circuits between terminals 1 + 2 and 1 + 3. Specification: Infinity Ohms

If specified values are not obtained:
- Replace engine speed (RPM) sensor -G28-

If no DTC is found on sensor:







- Connect VAG 1598/31 adapter cable to control module wiring harness. Engine Control Module (ECM) is not connected.







- Check wires between test box and 3-pin connector for open circuits according to wiring diagram.
Terminal 3 + socket 82
Terminal 2 + socket 90
Terminal 1 + socket 108
Wire resistance: max: 1.5 Ohms
- Also check wires for short circuit to each other.

If no malfunctions are found in wires:
- Remove sensor and check sensor wheel for secure fit, damage, and run-out.


NOTE: There is a larger-sized gap on the sensor wheel. This gap is a reference mark, not damage.


If nothing seems to be wrong with the sensor wheel:
- Replace Engine Control Module (ECM).