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Test 9A: Modulator Fault

NOTE: For connector terminal identification, refer to CONNECTOR IDENTIFICATION . For wiring diagrams, refer to WIRING DIAGRAMS .
NOTE: When modulator assembly connector is disconnected, PUMP/MOTOR fault will be set. Disregard this fault.
  1. Turn ignition on. Disconnect modulator assembly 10-pin connector. Modulator assembly is located under battery tray. Using DRB, actuate left front build/decay valve. Hydraulic valve tests will cycle on and off for approximately 6 minutes. It may be necessary to reactivate test if too much time elapses. If DRB does not display left front build/decay valve switching between LF BUILD and LF DECAY, replace Controller Anti-Lock Brake (CAB). Perform TEST VER-1A: SYSTEM VERIFICATION TEST . If DRB displays left front build/decay valve switching between LF BUILD and LF DECAY, go to next step.
  2. Put DRB in voltmeter mode. Ensure DRB is still actuating left front build/decay valve. Using DRB, check voltage on Brown/Yellow wire at modulator assembly 10-pin connector. See Figure. If voltage is not switching between zero and 12 volts, go to TEST 9B. If voltage is switching between zero and 12 volts, go to next step.
  3. Using DRB, stop actuation test. Actuate left rear build/decay valve. If DRB does not display left rear build/decay valve switching between LR BUILD and LR DECAY, replace CAB. Perform TEST VER-1A: SYSTEM VERIFICATION TEST . If DRB displays left rear build/decay valve switching between LR BUILD and LR DECAY, go to next step.
  4. Put DRB in voltmeter mode. Ensure DRB is still actuating left rear build/decay valve. Using DRB, check voltage on Brown/Light Blue wire at modulator assembly 10-pin connector. If voltage is not switching between zero and 12 volts, go to TEST 9C. If voltage is switching between zero and 12 volts, go to next step.
  5. Using DRB, stop actuation test. Actuate right front build/decay valve. If DRB does not display right front build/decay valve switching between RF BUILD and RF DECAY, replace CAB. Perform TEST VER-1A: SYSTEM VERIFICATION TEST . If DRB displays right front build/decay valve switching between RF BUILD and RF DECAY, go to next step.
  6. Put DRB in voltmeter mode. Ensure DRB is still actuating right front build/decay valve. Using DRB, check voltage on Dark Green/Yellow wire at modulator assembly 10-pin connector. If voltage is not switching between zero and 12 volts, go to TEST 9D. If voltage is switching between zero and 12 volts, go to next step.
  7. Using DRB, stop actuation test. Actuate right rear build/decay valve. If DRB does not display right rear build/decay valve switching between RR BUILD and RR DECAY, replace CAB. Perform TEST VER-1A: SYSTEM VERIFICATION TEST . If DRB displays right rear build/decay valve switching between RR BUILD and RR DECAY, go to next step.
  8. Put DRB in voltmeter mode. Ensure DRB is still actuating right rear build/decay valve. Using DRB, check voltage on Dark Green/Light Blue wire at modulator assembly 10-pin connector. If voltage is not switching between zero and 12 volts, go to TEST 9E. If voltage is switching between zero and 12 volts, go to next step.
  9. Turn ignition off. Put DRB in ohmmeter mode. Using DRB, check resistance of modulator assembly 10-pin connector terminal No. 1 (Black wire). See Figure. If resistance is more than 5 ohms, repair open in Black wire. Perform TEST VER-1A: SYSTEM VERIFICATION TEST . If resistance is less than 5 ohms, go to next step.
  10. Using DRB, check resistance of modulator assembly 10-pin connector terminal No. 10 (Black wire). See Figure. If resistance is more than 5 ohms, repair open in Black wire. Perform TEST VER-1A: SYSTEM VERIFICATION TEST . If resistance is less than 5 ohms, reconnect modulator assembly 10-pin connector. Go to TEST 9F.
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