Audi Workshop Service and Repair Manuals

Notes:

• ◆ The engine speed sensor is a combined speed sensor and reference mark sensor.
• ◆ The engine cannot be started without a signal from the -G28 engine speed sensor.
• ◆ If the signal from the -G28 engine speed sensor fails while the engine is running, the engine will cut out immediately.

Checking the engine speed sensor

Fitting location for the sensor and connector
.

• ‒ Before carrying out the test, make sure that the sensor is correctly installed and firmly seated.
• ‒ Unplug the connector for the engine speed sensor (identification: grey connector).

• ‒ → Connect the V.A.G 1526 hand held multimeter for resistance measurement to contacts 2 and 3 on the connector.

• Specified value: approx. 450...1000 ω.

If the specified value is not achieved:

• ‒ Replace the engine speed sensor.

If the specified value is achieved:

• ‒ Connect the V.A.G. 1526 hand-held multimeter for resistance measurement between contacts 2 and 1 (earth) and to contacts 3 and 1 (earth).

• Specified value: infinity in each case ω (no continuity).

If the specified value is not achieved:

• ‒ Replace the engine speed sensor.

If the specified value is achieved:

• ‒ → Check the wiring between the sensor connector and the engine control unit as follows:
• ‒ Connect the V.A.G 1598/22 test box to the wiring harness for the engine control unit
  .

• ‒ → Check the wiring from the 3 pin connector (sensor connector) ...
• ‒ ... to the engine control unit for an open circuit and short to positive or earth. Check the earth.

• ‒ If necessary, rectify open circuit or short circuit.