1987 Audi 5000 CS, AutomaticFACTORY OEM SERVICE PROCEDURE

All Models

  1. Item Being Tested - Left Front Wheel Speed Sensor Signal Raise vehicle on hoist until all 4 wheels are free to rotate. Release parking brake. On 5000CS Quattro, disengage differential locks. On all models, place gear selector lever in Neutral.
  2. Place ABS tester in program switch position No. 23. Press button No. 8. Spin left front wheel by hand at about one revolution per minute. As wheel is being rotated, note voltage reading on ABS tester.
  3. Voltage reading on tester should be between 1.7-19 volts. If voltage varies, use lowest value obtained. If reading is close to 1.7 volts, check speed sensor (PVC tip) air gap. See the following:
  4. If reading is below 1.7 volts (except zero), replace speed sensor. If voltage reading is zero volts, check speed sensor wiring for damage, open circuits, or reversed leads. See Figure .
  5. If reading on ABS tester is 999 volts, wheel is being spun too fast. Rotate tire at a lower speed and repeat test. If reading is correct, go to next step.
  6. Item Being Tested - Right Front Wheel Speed Sensor Signal Press button No. 9. Spin right front wheel by hand at about one revolution per minute. As wheel is being rotated, note voltage reading on ABS tester. If voltage reading is correct, go to next step. If reading is incorrect, use steps 3) through 5) to determine corrective action.
  7. Item Being Tested - Left Rear Wheel Speed Sensor Signal Press button No. 11. Spin left rear wheel by hand at about one revolution per minute. As wheel is being rotated, note voltage reading on ABS tester. If voltage reading is correct, go to next step. If reading is incorrect, use steps 3) through 5) to determine corrective action.
  8. Item Being Tested - Right Rear Wheel Speed Sensor Signal Press button No. 12. Spin right rear wheel by hand at about one revolution per minute. As wheel is being rotated, note voltage reading on ABS tester. If voltage reading is correct, go to FINAL CHECK. If voltage reading is incorrect, use steps 3) through 5) to determine corrective action.
NOTE: If fault in ABS system has not been determined by the time TEST 23 has been carried out, replace hydraulic modulator.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.