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80/90 QUATTRO & 5000CS QUATTRO

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  1. Item Being Tested - Voltage Supply Circuit Place ABS tester in program switch position No. 1 and turn ignition on. Lamp No. 1 (Green) must come on (also applies to all other program switch positions). If lamp comes on, go to step 7). Lamps No. 2 or 3 may also come on. Disregard lamps No. 2 and 3 at this time.
  2. If lamp No. 1 did not come on, check ABS control unit and tester plug connectors for tightness. If okay, remove anti-lock power supply relay from auxiliary relay panel (position No. 5).
  3. Connect voltmeter between contacts No. 2 and 4, and then between contacts No. 4 and 5. Voltmeter readings should be about 12 volts. If incorrect, repair break in wiring harness. If correct, go to next step.
  4. Connect voltmeter between contacts No. 4 and 8. Press and hold anti-lock switch. Voltmeter reading should be about 12 volts. If incorrect, repair break in wiring harness or replace anti-lock switch. If correct, go to next step.
  5. Connect voltmeter between contacts No. 1 and 5, and then between contacts No. 3 and 5. Lock center and rear differentials (No. 1 and 2). With differentials locked, voltmeter reading should be about 12 volts.
  6. With differentials unlocked, voltmeter reading should be close to zero volts. If readings are incorrect, repair wiring harness or replace differential lock switch. If readings are correct, go to next step.
    NOTE: If differential locks do not engage (warning lights do not light up), turn a wheel on front or rear axle until differential lock engages or disengages.
  7. With ABS tester in program switch position No. 1 and ignition on, lamp No. 1 (Green) must be on (also applies to all other program switch positions). If lamp is on, go to step 13). If not, go to next step.
  8. Unclip relay socket No. 5 from auxiliary relay panel. Install anti-lock power supply relay in disconnected socket No. 5. Connect voltmeter between contacts No. 4 and 6.
  9. Voltmeter reading should be about 12 volts. If reading is incorrect, check fuse and anti-lock relay or replace anti-lock power supply relay. If reading is correct, go to next step.
  10. Remove anti-lock power supply relay out of socket and insert socket into auxiliary relay panel at location No. 5. Install anti-lock power supply relay. Turn ignition off.
  11. Using ohmmeter, check ground wire between terminal No. 10 in ABS control unit plug and ground point under right rear seat kick panel. Ohmmeter reading must be close to zero ohms. If reading is incorrect, repair wiring harness or contact resistance. If reading is correct, go to next step.
  12. Turn ignition on and connect voltmeter between terminal No. 1 and 10 in ABS control unit plug. See Figure - Figure . Voltmeter reading should be about 12 volts. If reading is incorrect, repair wiring harness. If reading is correct, go to next step.
    NOTE: If lamp No. 2 comes on, battery is not fully charged or there is an excessive voltage drop at terminal No. 1 or 10 of ABS control unit plug. If lamp No. 2 comes on during subsequent test procedure, stop test procedure and eliminate fault. After repairs repeat entire test procedure.
  13. Item Being Tested - Solenoid Valve Relay (Off Position) With ABS tester in program switch position No. 1 and ignition on, lamps No. 1 and 3 (Green) must come on. If lamps come on, TEST 1 is completed.
  14. If lamp No. 4 (Red) comes on, remove relay for solenoid valves from hydraulic modulator. Use ohmmeter to test continuity between terminals No. 87A and 30. Replace relay if no continuity exists. If correct, go to next step.
  15. Use ohmmeter to measure internal resistance of solenoid valve relay between terminals No. 85 and 86. Ohmmeter reading should be 70-120 ohms. If incorrect, replace solenoid valve relay. If correct, go to next step.
  16. Turn ignition off and disconnect plug for hydraulic modulator. Use ohmmeter to check continuity of ground lead to terminal No. 8. If necessary, repair wiring harness. If continuity exists, go to next step.
  17. Use ohmmeter to check continuity between terminal No. 8 in socket of hydraulic modulator and terminal No. 87A on relay socket for solenoid valves. SeeFigure - Figure . If there is no continuity, replace hydraulic modulator. If continuity exists, go to next step.
  18. Use ohmmeter to check continuity between terminal No. 12 in socket of hydraulic modulator and terminal No. 30 in socket for solenoid valves. If there is no continuity, replace hydraulic modulator. If continuity exists, go to next step.
  19. Use ohmmeter to check continuity between terminal No. 12 in plug for hydraulic modulator and terminal No. 32 on plug for ABS control unit. If necessary, repair wiring harness.
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