Engine Speed (RPM) Sensor -G28-, Checking

Engine speed (RPM) sensor -G28-, checking

NOTE: The engine speed sensor is a combined speed sensor and reference mark sensor.

Checking engine speed sensor
- Before performing the check, ensure that the sensor is correctly installed and firmly seated.
- No debris or damage to speed sensor or wheel sensor.
- The thickness of the plate between the sensor and the automatic transmission must be 4.5 mm.
- Disconnect connector for engine speed sensor (identification: gray connector).







- Connect hand-held multimeter VAG 1526 (resistance test range) to contacts 2 and 3 on connector for engine speed sensor using test lead from VAG 1594.
Specified value: approx. 450...1000 Ohm

NOTE:
- The resistance figure for the engine speed sensor is associated with a temperature of 20 degrees C.
- The resistance increases with increasing temperature.

If specification is not attained:
- Install a new engine speed sensor.

If the specified value is achieved:







- Connect VAG 1526 hand-held multimeter for resistance measurement between contacts 2 and 1 (Ground) as well as to contacts 3 and 1 (Ground).
Specified value: infinity Ohm in each case (no continuity).

If specification is not attained:
- Install a new engine speed sensor.

If the specified value is achieved:
- Check wiring between sensor connector and engine control module as follows:

Wiring connections between engine speed sensor and engine control module

- Connect test box VAG 1598/31 to wiring harness for engine control module; do not connect engine control module. Connecting VAG 1598/31 Test Box







- Check wiring from 3-pin connector (sensor connector) ...
- ... to engine control module for checking for open circuit and short to positive or Ground.

3-pin connector on
wiring harness,socket Test box VAG 1598/31,socket
1 (screening) 108
2 (Ground wire) 90
3 (signal wire) 82

Wire resistance: max. 1.5 Ohm

- Correct any open/short circuit as necessary.

If no wiring malfunctions are detected:
- Slowly turn engine and check sensor wheel for concentricity/tight fit.

If no malfunctions have been found in any of the above checks:

- Install a new engine control module.
- Read readiness code. Generate readiness code again if DTC memory was erased. Readiness Code, Generating