Code 22, Right Front Speed Sensor
- Turn ignition off. Unplug ABS/AWD control unit. Using a DVOM, measure speed sensor resistance between pins No. 46 and 47 of ABS/AWD control unit wiring harness. Sensor resistance should be 600-1600 ohms.
- If resistance is incorrect, check wiring harness between ABS/AWD control unit and right front speed sensor (including pins/connectors). If circuit is okay, replace speed sensor.
- If resistance is correct, check speed sensor voltage signal at plug (on spring strut mount in trunk). See Fig 1 . Connect oscilloscope to speed sensor wire.
- Depending on oscilloscope, select special input or secondary image display. Turn right front wheel by hand, at about one revolution per second.
- Oscilloscope should display of 2 volts, as measured peak to peak. If voltage signal is incorrect, ensure speed sensor air gap is correct. Ensure wheel bearing or pulse wheel is not damaged or corroded. Repair as necessary.
NOTE:
Code 21, 22, 23 and 24 may also be set if a Porsche 928 ABS/PSD control unit is accidentally installed in a 911. Ensure first 6 digits of ABS/AWD control unit are 964 618 #-- ---.