Engine Speed Sensor: Testing and Inspection

Engine Speed Sensor, 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 workshop equipment required
- VAG1526 multimeter or VAG1715 multimeter
- VAG1594 connector test kit
- Wiring diagram

Test sequence, Engine code AXK







- Disconnect gray 3-pin harness connector (arrow) leading to the engine speed (RPM) sensor -G28-.







- Measure resistance of sensor between terminals 2 + 3 at connector to sensor.
Specification: 480 to 1000 Ohms
- Check sensor for shorts between terminals 1 + 2 and 1 + 3. Specification: Infinity Ohms

If specified values are not obtained:
- Replace engine speed (RPM) sensor -G28-
- Erase DTC memory of Engine Control Module (ECM): Diagnostic Mode 4: Reset/erase diagnostic data.
- Generate Readyness code

If no malfunction is found on sensor:


- Connect test box to control module wiring harness for wiring test.
- Check wires between test box and 3-pin connector for open circuits according to wiring diagram.

Terminal 1 + socket 108
Terminal 2 + socket 90
Terminal 3 + socket 82

Wire resistance: max: 1.5 Ohms







- Check wires for short circuit to each other, to vehicle Ground (GND) and to B+

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 and does not mean ttat the sensor wheel is damaged.


If nothing seems to be wrong with the sensor wheel:
- Replace Engine Control Module (ECM) -J220-.