Engine Speed (RPM) Signal, Checking

NOTES:
- The RPM signal is required for the tachometer, ABS control module and the A/C system.
- The RPM signal, generated by the Engine Speed (RPM) sensor -G28-, is processed and distributed by the Engine Control Module (ECM).


Check RPM signal as follows:
- Connect VAG 1551 Scan Tool (See page 01-5) and press -0- button twice, to select "Automatic Test Sequence" function 00. [1][2]Scan Tool Connecting and Initial Checks
There must be no malfunctions stored in Diagnostic Trouble Code (DTC) memory that refer to "Missing RPM Signal."

If DTCs indicating missing RPM signal are stored:
- Check wiring for short circuit between appropriate control module and ECM.
See Electrical Wiring Diagrams, Troubleshooting and Component Locations.