 | ||||||||||||||||||||||||||||||||||||
|
||||||||||||||||||||||||||||||||||||
|
How to Diagnose A Problem with Honda's ABSPosted 9/9/2003By Wayne Pasicznyk
Honda's anti-lock brake systems (ABS) were first developed in the late 1980s on some models. In 1994, a compact ABS unit, located under the hood, was used primarily on the 1994-'97 Accord and the 1995-'97 Odyssey. This compact unit featured an ABS pump, modulator and accumulator (an all-in-one unit) with all the solenoids and the pressure switch built into the modulator unit. All Honda ABS systems had a separate reservoir for the ABS brake fluid until the late 1990s. When the ABS reservoir is low or empty, it draws air into the ABS side of the system and causes the ABS light to illuminate. The most common call I receive is on Code 1. When flashed out, Code 1 is a single flash followed by a 5-second pause that repeats three times. Code 1 is a pump-overrun code. The ABS control unit is programmed to set a Code 1 when it thinks that the pump has been running for more than 45 seconds, or the pressure switch does not close, or if the pressure in the ABS system is insufficient. Code 1 Diagnostics: Verify the ABS fluid reservoir is full. If the reservoir is low or empty, there may be air in the ABS system. Always remember the regular brake system and the ABS system should never transfer brake fluid between each other. Fill the reservoir as needed, and perform the following procedure to bleed the air out of the ABS system: 1) Start the engine and allow the ABS pump to run. (If the ABS pump does not run, separate diagnostics will need to be run on the ABS pump motor operation.) 2) When the ABS pump stops running, attach a hose to the brake bleeder on top of the ABS unit and run it into a container. 3) Open the bleeder. Check to see if the fluid is full of air or if any fluid comes out. If it's full of air, top off the ABS reservoir and repeat the procedure until all the air is out of the system. If little or no fluid comes out, apply pressure to the ABS reservoir using a handheld vacuum pump to push the air out and help the ABS pump pick up the fluid. Attach the vacuum hose to the port on the vacuum pump where pressure is released during operation. The port may be covered with a cap - just remove it and attach the hose. 4) Attach the quarter-size round disc (found in most vacuum pump kits) to the other end of the vacuum hose to cover the filler hole on the top of the ABS reservoir. 5) Start the engine. As the ABS pump runs, apply pressure against the ABS fluid in the reservoir to help the ABS pump pick up the brake fluid. There are many ways to pressurize the ABS reservoir. DO NOT overpressure. A noticeable change in the sound of the ABS pump motor should occur when it starts to build pressure. 6) After the pump shuts off, try bleeding the system again. If brake fluid bleeds out, repeat the procedure until the air is totally out of the system. Always remember to keep the ABS reservoir full of brake fluid. If no fluid bleeds out, most likely the ABS pump has failed and won't produce pressure. If this procedure works and the ABS pump can achieve pressure in the 45-second time frame, Code 1 will not reset. Note: Remembering these basic steps will help you diagnosis the problem in less time.
|
|||||||||||||||||||||||||||||||||||
Copyright (c) 1996-2008. Automotive Service Association. All rights reserved.
 | ||||||||||||||||||||||||||||||||||||
This information is provided by IDENTIFIX®. IDENTIFIX® resources cut diagnostic time and provide repair solutions that increase the shop's bottom line. From Repair-Trac pattern failure quick fixes, to Diagram-Online wiring diagrams by fax, to the Repair Hotline staffed by 32 master techs who specialize in diagnosing complex problems by phone or fax, IDENTIFIX® helps techicians fix more cars in less time.
