Engine Speed (RPM) Sensor, Checking

Engine speed (RPM) sensor, checking

Function
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.

Recommended special tools and equipment
- VAG1526 multimeter or VAG1715 multimeter
- VAG1594 connector test kit
- Wiring diagram

Test sequence






- Disconnect 3-pin harness connector -2- to engine speed (RPM) sensor -1-.






- Measure sensor resistance between terminals 2 + 3 at connector to sensor.
Specified value: 480 to 1000 Ohms

- Check sensor for shorts between terminals 1 + 2 and 1 + 3.
Specified value: Infinite Ohms

If specified values are not obtained:
- Replace Engine Speed (RPM) Sensor -G28-.
- Erase DTC memory of Engine Control Module (ECM).
- Generate readiness code.

If no DTC is found on sensor:
- Connect test box to control module wiring harness.

Vehicles > 08.99






- Check wires between test box and 3-pin connector to Engine Control Module (ECM) for open circuit according to wiring diagram.
Terminal 1 + socket 67
Terminal 2 + socket 68
Terminal 3 + socket 56
Wire resistance: max: 1.5 Ohms

Vehicles 09.99 >






- Check wires between test box and 3-pin connector to Engine Control Module (ECM) for open circuit according to wiring diagram.
Terminal 1 + socket 56
Terminal 2 + socket 63
Terminal 3 + socket 67
Wire resistance: max: 1.5 Ohms

Continuation for all vehicles
- Check wires for short circuit to each other, to vehicle Ground (GND) and to B+.
Specified value: Infinite Ohms

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 the reference mark and does not mean that the sensor wheel is damaged.

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