Engine Speed (RPM) Sensor -G28-, Checking

Engine Speed (RPM) Signal -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 multimeter (Fluke 83 or equivalent) (resistance test range) to terminals 2 and 3 on connector for engine speed sensor using test lead from VAG1594 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 sensor.
If the specification is attained:
- Connect multimeter (Fluke 83 or equivalent) (resistance test range) between terminals 2 and 1 (Ground (GND)) and between terminals 3 and 1 (Ground (GND)).

Specification: R Ohms (infinite Ohms/open circuit) in each test

If the specification is not attained:
- Replace engine speed sensor. If the specification is attained:
- Check wiring between sensor connector and engine control module as follows:
- Connect VAG1598/31 test box to wiring harness for engine control module. Do not connect to the engine control module itself. Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/Connecting VAG1598/31 Test Box" Testing and Inspection







- 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 wiring
harness, contact Socket VAG1598/31 test box
1 (shielded) 108
2 (Ground (GND) wire) 90
3 (signal wire) 82

Resistance in wiring: max. 1.5 ohm

- Repair any open/short circuit as necessary. If no malfunctions are identified in the wiring:
- Slowly turn over the engine and check that sensor wheel has no run-out and is securely mounted.
- If no malfunctions have been identified in any of the tests so far, replace Engine Control Module (ECM).
- Display readiness code. If DTC memory was erased generate readiness.
Refer to "Monitors, Trips and/or Drive Cycle (Readiness Codes)/Readiness Code" Testing and Inspection
Refer to "Monitors, Trips and/or Drive Cycle (Readiness Codes)/Generating Readiness Code" Testing and Inspection