With Manufacturer's Scan Tool
Engine Speed (RPM) Sensor, Checking
The engine speed (RPM) 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 and equipment
- Scan tool VAG 1551 or vehicle system tester V.A.G 1552 with cable VAG 1551/3B
- Test box V.A.G 1598/31
- Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
- Adapter set V.A.G 1594
- Wiring diagram
Test sequence
- Separate grey 3-pin connector -1- to engine speed sensor.
- Measure sensor resistance between terminals 2 + 3 of connector to sensor.
Specification: 730 to 1000 Ohms
NOTE: The resistance figures are valid for approx. 20 °C. At higher temperatures the resistance figures will increase.
- Check the sensor for short between terminals 1 + 2 as well as 1 + 3.
Specification: Infinity Ohms
If the specifications are not obtained:
- Replace engine speed sensor (G28)
- Check DTC memory, if necessary, repair any malfunctions and then erase DTC memory. Reading Diagnostic Trouble Codes
- Read readiness code. If DTC memory has been erased or engine control module was disconnected from permanent positive, readiness code must be generated again.
Monitors, Trips, Drive Cycles and Readiness Codes
Monitors, Trips, Drive Cycles and Readiness Codes
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. Engine control module is not connected by this action.
- Check wiring for open circuit between test box and 3-pin connector using wiring diagram.
- Terminal 1 + socket 108
- Terminal 2 + socket 90
- Terminal 3 + socket 82
Wire resistance: Max. 1.5 Ohms
- Additionally check wires for short to one another.
Specification : Infinity Ohms
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).