Engine Speed Sensor: Testing and Inspection

Engine Speed (RPM) Sensor -G28-, Checking







Recommended special tools and equipment
- V.A.G 1526A multimeter
- V.A.G 1594A connector test kit
- V.A.G 1598/31 test box

NOTE: The engine speed (RPM) sensor -G28- detects RPM and reference marks. The engine cannot be started without a signal from the engine speed (RPM) sensor -G28-. If the engine speed (RPM) sensor -G28- signal fails while the engine is running, the engine will stop immediately.

Test requirement:
- Ignition switched off.

Procedure
- Before performing test, check sensor for proper installation and proper fitting.







- Remove coolant reservoir -2- -arrows-
- Disconnect electrical wire from Engine Coolant Level (ECL) Warning Switch -F66- and set aside coolant reservoir with coolant hoses -1- and -3- connected.







- Disconnect electrical harness connector -2- from Engine Speed (RPM) Sensor -G28-.

Checking internal resistance







- Connect multimeter between terminal 2 and 3 for resistance measurement.
- Specified value: 450 to 1000 ohm

NOTE: Resistance value of the engine speed (RPM) sensor is based on a temperature of 20 degrees C. Resistance increases as temperature increases.

If specified value is not obtained:
- Replace Engine Speed (RPM) sensor.

If specified value is obtained:







- Connect multimeter to terminals 2 and 1 (shielding) as well as to terminals 3 and 1 (shielding) for resistance measurement.
- Specified value: each Infinite Ohms (no continuity)

If specified value is not obtained:
- Replace Engine Speed (RPM) sensor.

If specified value is obtained:

Checking wire connections
- Connect test box to wiring harness of Engine Control Module (ECM), ECM is not connected. Test Box, Connecting For Wiring and Component Test







- Check the following wire connections for open circuit according to wiring diagram:

Harness connector Terminal Test box Socket
1 (shielding) 108
2 Ground (GND) 90
3 (signal) 82

Specified value: Wire resistance max 1.5 Ohms

- Check wires for short circuit to each other as well as to B+ and Ground (GND).
- Specified value: Infinite Ohms (no continuity)
- If necessary, repair wire connection.

If no malfunctions are detected:
- Replace Engine Control Module (ECM).

Assembly is performed in reverse order of removal, note the following:

Final procedures
After repair work, the following work steps must be performed in the mentioned sequence:
1. Check DTC memory see "Mode 3: Check DTC memory". Mode 3: Check DTC Memory
2. If necessary, erase DTC memory see "Mode 4: Reset/erase diagnostic data". Mode 4: Reset/Erase Diagnostic Data
3. Generate readiness code. Readiness Code, Generating

- End diagnosis and switch ignition off.