Engine Speed Sensor: Testing and Inspection

Engine Speed (RPM) Sensor -G28-, Checking

The engine speed sensor (G28) is a speed and reference mark sender. 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
- VAG1551 scan tool or VAG1552 mobile scan tool with VAG1551/3B cable
- VAG 1598/31 test box
- VAG1526 hand multimeter or VAG1715 multimeter
- VAG1594 adapter set
- Wiring diagram

Test sequence







- Separate gray 3 pin connector -1- to engine speed sensor.







- Measure sensor resistance between contacts 2 + 3 of connector to sensor.
Specification: 730 to 1000 Ohm
- Check sensor for short between contacts 1 + 2 as well as 1 + 3.
Specification: Infinity Ohm

If the specifications are not obtained:
- Replace engine speed sensor (G28).
- Check DTC Memory, if necessary, repair any malfunctions and then Erase DTC Memory,Checking and Erasing DTC Memory. Refer to "Displaying and Reading Trouble Codes/With Manufacture Scan Tool/Check DTC Memory (Function 02)" Testing and Inspection
- Read readiness code. If DTC memory has been erased or engine control module was disconnected from permanent positive, readiness code must be generated again: Refer to "Monitors, Trips and/or Drive Cycle/ Reading Readiness Code" Testing and Inspection
Engine code AWW, Refer to "Monitors, Trips and/or Drive Cycle/Generating Readiness Code" Testing and Inspection
Engine code AWP, Refer to "Monitors, Trips and/or Drive Cycle/Generating Readiness Code" Testing and Inspection

If no sender malfunction is detected:







- Connect VAG1598/31 test box to control module wiring harness. The engine control module remains disconnected.







- Check wiring between test box and 3-pin connector for open circuit using wiring diagram.
Contact 1+socket 108
Contact 2+socket 90
Contact 3+socket 82
Wire resistance: Max. 1.5 Ohm
- Additionally check wires for short to one another.

If no wiring fault 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.