Engine Speed Sensor, 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 carrying out the test, make sure that sensor is correctly installed and firmly seated.

- Check sensor and sensor wheel for damage and make sure they are not obstructed by metal particles.

Thickness of spacer between sensor and transmission should be 4.5 mm.

- Disconnect harness connector for engine speed sensor (grey connector).
- Connect VAG 1526 multimeter (resistance test range) to terminals 2 and 3 on connector for engine speed sensor using test lead from VAG 1594 connector test kit.







Specification: approx. 450 to 1000 ohm

NOTE:
- The resistance value for the engine speed sensor is based on a temperature of 20 ° C.
- The resistance increases as the temperature rises.

If the specification is not attained:
- Replace Engine Speed (RPM) sensor.

If the specification is attained:
- Connect multimeter VAG 1526 (resistance test range) between terminals 2 and 1 (Ground) and between terminals 3 and 1 (Ground).







Specification: R ohms (infinity / open circuit) in each test

If the specification is not attained:
- Replace Engine Speed (RPM) sensor.

If the specification is attained:

Check wiring between sensor connector and engine control module as follows:

- Connect VAG 1598/31 test box to wiring harness for engine control module. DO NOT connect to engine control module itself, Connecting VAG 1598/31 Test Box

- Check wiring connection from 3-pin connector (sensor connector) to engine control module for open circuit and/or short circuit to B+ or Ground (GND)







3-pin connector on Socket on VAG
wiring harness, 1598/31 test box
contact
1 (shielded wire) 108
2 (Ground (GND) wire) 90
3 (signal wire) 82

Resistance in wiring: max. 1.5 ohm

- Correct any open/short circuit as necessary.

If no malfunctions are identified in the wiring:
- Slowly turn engine over and check that sensor wheel has no run-out and is securely mounted.
- If no malfunctions have been identified in any tests so far, replace Engine Control Module (ECM).
- Display readiness code, Readiness Code Reading. If DTC memory was erased generate readiness code, Readiness Code, Generating