Engine Speed Sensor
- This sensor can only be tested using an oscilloscope. To do so, set-up and adjust oscilloscope using manufacturer instructions.
- Disconnect DME control unit. Connect positive test lead to terminal No. 47 (White wire) and negative lead to terminal No. 48 (Brown wire) of DME control unit wiring harness connector. Crank engine and observe reading.
- Oscillations of at least 3 volts and an intermediate higher amplitude (reference mark) signal must display. See Fig 1
. If necessary, connect oscilloscope leads to terminal No. 1 (White wire) and terminal No. 2 (Brown wire) at sensor.
Courtesy of PORSCHE OF NORTH AMERICA, INC.
- 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).
- 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 2
. Align a flywheel tooth to center of sensor opening. Measure ring gear tooth depth and sensor length. Difference between ring gear tooth depth and sensor length must be 0.03-0.05" (0.8-1.2 mm). If necessary, add or remove adjustment shim(s). Adjust sensor until air gap between ring gear and sensor is 0.04" (1 mm).
Courtesy of PORSCHE OF NORTH AMERICA, INC.