My 2002 Subaru Outback sport (based on the imprezza) displays the same problem with the ABS system being ineffective when braking over bumps as the 2002, 2003 wrxs currently being investigated by ODI (PE03-029). This problem is not just limited to the WRX vehicle. The problem is clearly demonstrated under light to moderate braking effort, if the vehicle encounters a sharp bump (e.g. a raised pavement section at an expansion joint) while the brakes are applied. Normal ABS function would momentarily ease up the braking pressure on the front wheels as they become un-weighted on the back side of the bump, so that they do not lock-up. After the front wheels are fully weighted again the ABS system would allow the previous braking effort to be re-established allowing the car to stop almost normally. Thus the braking distance of the vehicle might be extended by the length of the bump (perhaps 6 inches). This correct behavior is exhibited by my 1994 probe GT. If I drive my Subaru over the same road conditions, when the vehicle hits a sharp bump, the ABS system start functioning and continues for a significant period of time, even after passing over the bump. This, in itself, should not be a problem, but during this time the braking efficiency is drastically reduced. This typically extends the stopping distance of the Subaru by 10-30 feet (when stopping from 30mph) over what would have been achieved if the bump had not occurred. If I immediately release the brake peddle, and then fully apply the brakes the car does stop. So this problem is not associated with the tireS ability to grip the road, or the brakeS ability to stop the rotor/drum. I believe it to be a programming error in the ECU. This problem is repeatable and fully demonstrable. I would be happy to supply further details to help get this issue resolved.

- Livonia, MI, USA