LEMON Manuals: Even more car manuals for everyone
Home >> Mitsubishi >> 2003 >> Montero XLS >> Repair and Diagnosis >> Brakes >> Mechanical - Hydraulic >> Hydraulic Brake Booster >> Diagnostic Tests >> DTC 53: Motor Relay >> Diagnosis & Repair

Diagnosis & Repair

NOTE: For component location and connector identification, see Figure .
  1. Check if HBB buzzer sounds. If HBB buzzer does not sound, go to next step. If HBB buzzer sounds, check pump motor for seizure. If pump motor is seized, replace HBB, then go to step  10 .
  2. Check connectors B-17 and B-18 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If problem is found, repair as necessary, then go to step  10 . If problem is not found, go to next step.
  3. Disconnect HBB connector B-17. Measure resistance between ground and terminal No. 7. See Fig 1 . If resistance is less than 2 ohms, go to next step. If resistance is not less than 2 ohms, repair wire between HBB connector B-17 and ground, then go to step  10 .
    Fig 1: Checking HBB Ground Circuit At Connector B-17
    G00301930Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
  4. Disconnect HBB connector B-18. Measure resistance between ground and terminal No. 32. See Fig 2 . If resistance is less than 2 ohms, go to next step. If resistance is not less than 2 ohms, repair wire between HBB connector B-18 and ground, then go to step  10 .
    Fig 2: Checking HBB Ground Circuit At HBB Connector B-18
    G00301931Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
  5. With HBB connectors B-17 and B-18 disconnected, measure resistance between HBB terminals as specified in illustration. See Fig 3 . If resistance is as specified in illustration, go to step  7 . If resistance is not as specified in illustration, go to next step.
    Fig 3: Checking HBB Resistance
    G00313686Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
  6. Remove HBB. See HYDRAULIC BRAKE BOOSTER  under REMOVAL & INSTALLATION. Remove pump motor and lead wire from HBB. See HYDRAULIC BRAKE BOOSTER  under OVERHAUL. Check that pump motor operates when battery voltage is applied. Also, check continuity of lead wire. If problem is found, repair as necessary, then go to step  10 . If pump motor and lead wire are in good condition, replace master cylinder and hydraulic unit assembly.
  7. Check M-ASTC-ECU connector E-119 for loose, corroded or damaged terminals, or terminals pushed back in the connector. If connector and terminals are in good condition, go to next step. If connector and terminals are not in good condition, repair as necessary, then go to step  10 .
  8. Check the following wires:
    • Wire between HBB connector B-17 terminal No. 4 and M-ASTC-ECU connector E-119 terminal No. 25.
    • Wire between HBB connector B-17 terminal No. 6 and M-ASTC-ECU connector E-119 terminal No. 12.
    • Wire between HBB connector B-17 terminal No. 8 and M-ASTC-ECU connector E-119 terminal No. 14.

    If problem is found, repair as necessary, then go to step  10 . If problem is not found, go to next step.

  9. Clear DTC memory. Recheck for DTC. If DTC 53 is set, replace M-ASTC-ECU, then go to next step. If DTC 53 is not set, it can be assumed that this malfunction is intermittent.
  10. Clear DTC memory. Recheck for DTC. If DTC 53 is set, go to step  1 . If DTC 53 is not set, repair is complete.
scientia non olet · About LEMON Manuals