With Manufacturer's Scan Tool

Engine Speed (RPM) Signal, Checking

Vehicles with automatic transmission

NOTE:
- The signal is generated by the Engine speed (RPM) sensor -G28- processed in the Engine Control Module (ECM) and directed to various parts of the electronic system (e.g. control module for A/C or ABS / EDS) from terminal 37 of the ECM. Engine speed signal and wire connections are monitored by these systems.
- Checking Engine speed (RPM) sensor -G28- Engine Speed (RPM) Sensor -G28-, Checking
- Connect test box V.A.G 1598/31 to wiring harness for Engine Control Module (ECM); do not connect ECM. Test Box, Connecting For Wiring and Component Test
- Check for open circuit and short to positive (B+) or ground (GND) in following wiring connections:

Test box Instrument cluster
V.A.G 1598/31 terminal
Socket
37

- Repair any open/short circuit as needed.

If no problems with wiring are found:
- Checking CAN bus.