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 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, workshop equipment, testers, measuring instruments and auxiliary items required
- VAG 1551/1552 Scan Tool using VAG 1551/3 Adaptor cable
- VAG 1598/22 Test Box
- Fluke 83 multimeter
- VW 1594 Adaptor kit
- Wiring diagram

Requirement
- Battery Voltage must be 11.5 Volts minimum

Test sequence







- Disconnect grey 3-pin harness connector from Engine Speed sensor -arrow-.
- Measure sensor resistance between terminals 2 + 3 of connector -1-.
- Specification: 480 to 1000 Ohms
- Check sensor for short between terminals 1 + 2 and 1 + 3.
- Specification: Infinity Ohms

If specifications not obtained
- Replace Engine Speed sensor G28.

If sensor OK:







- Connect VAG 1598/22 Test Box to Control Module wiring harness. Check wiring for open circuit between Test Box and 3-pin harness connector -2- using Wiring diagram
Terminal 1 + socket 67
Terminal 2 + socket 63
Terminal 3 + socket 56

- Wire resistance: maximum 1.5 Ohms
- Also check wires for short to one another.
Specification: Infinity Ohms

If wiring OK:
- Remove sensor and check sensor wheel for secure fit, damage and run-out.
- Check that the spacer for the sensor is seated securely.


NOTE: One of the gaps on the sensor wheel is larger than the others. This larger gap is the reference mark and should not be interpreted as sensor wheel damage.


- Display the Readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
- If DTC memory was erased or if the ECM was disconnected from Battery +, set the Readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

If wiring OK and resistance measurement values OK
- Replace Engine Control Module.