Code 1: Pump Motor Overrun
- Start engine and allow to idle for one minute. Check pump motor and ABS light operation. If pump motor runs for 40 seconds then light comes on, go to next step. If pump motor and light do not operate as described, vehicle is okay at this time.
- Check fluid level in modulator reservoir. See Fig 1
. If fluid level is not okay, replace modulator. If fluid level is okay, bleed air from system. See BLEEDING BRAKE SYSTEM
. If ABS light goes out, air was mixed with brake fluid. System is now okay. If ABS light does not go out, turn ignition switch to OFF position and go to next step.
- Disconnect modulator 14-pin connector. Check continuity between terminal No. 4 (Yellow wire) and terminal No. 11 (Black wire) of 14-pin connector. If continuity exists, go to next step. If continuity does not exist, replace modulator unit.
- Turn ignition switch to ON position. Measure voltage between terminal No. 4 (Yellow wire) of 14-pin connector and ground. If battery voltage does not exist, go to next step. If battery voltage exists, check pressure switch ground connection. If ground connection is okay, repair open Black wire between pressure switch and ground.
- Backprobing connector, measure voltage between terminal No. 19 (Yellow wire) of ABS control unit 26-pin connector and ground. If battery voltage exists, repair open Yellow wire between pressure switch and ABS control unit. If battery voltage does not exist, check ABS control unit connectors. If connectors are okay, install known-good ABS control unit and retest.
Courtesy of AMERICAN HONDA MOTOR CO., INC.