Engine Speed/Crankshaft Position (CKP) Sensor

1. Sensor can be tested using an oscilloscope. Set-up and adjust oscilloscope using manufacturer's instructions.
2. Disconnect ECM. ECM is located under driver's seat. Connect positive lead to ECM connector terminal No. 78 (White wire) and negative lead to terminal No. 20 (Brown wire). See Fig 1. Crank engine and observe reading.
3. Oscillations of at least 3 volts and an intermediate higher amplitude (reference mark) signal must be displayed. See Fig 2. If necessary, connect oscilloscope leads to terminal No. 1 (White wire) and terminal No. 2 (Brown wire) at sensor.
   Fig 1: Identifying ECM Connector Terminals

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   Fig 2: Testing Engine Speed Sensor

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4. If voltage reading is less than 3 volts, distance between sensor and ring gear may be incorrectly adjusted. Adjust sensor until air gap between ring gear and sensor is 0.04" (1 mm). If necessary, add or remove adjustment shim(s).
5. To check air gap on vehicles with Tiptronic (automatic) transmission, remove right rear wheel and heater hose from heat exchanger. Remove engine speed sensor. See Fig 3.

Fig 3: Adjusting Engine Speed/Reference Mark Sensor (Tiptronic)

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