Question about bypassing RABS valve
 

Hey guys, my ABS light is on and I'm going to bypass the RABS valve to convert things back to standard rear brakes. My question regards the ABS sensor in the rear differential... According to what I've read the ABS sensor acts as a speed sensor for the Powertrain Conrol Module. I would assume if you disconnect the RABS computer module you would then not be sending vehicle speed data to the PCM. Does anyone know how this will affect engine performance? I would think it would to some degree as the PCM now would not know what the vehicle speed is.



Thanks.

Since your ABS light is on, I would suspect that the braking has reverted to "STANDARD" braking. This is the normal when ABS issue are seen by the computer. You should be able to disconnect the lead, however there's no garantee that the ABS light will go off, since disconnecting the wire would be the same as an "OPEN" in the signal causing the light to go "ON".

Since your engines fuel management system uses SPEED DENSITY, it doesn't look at the vehicle speed. "SPEED DENSITY" systems measure engine speed (in rpm) and load (manifold vacuum in kPa), then the computer calculates airflow requirements by referring to a preprogrammed lookup table. The table is a map of thousands of pre-programmed values that equates to the engines volumetric efficiency (VE) under varying conditions of throttle position and engine speed. Engine rpm is provided via a tach signal, while vacuum is transmitted via an intake manifold-mounted Manifold Air Pressure (MAP) sensor. Since air density changes with air temperature, an intake manifold-mounted sensor is also used along with the O2 sensor.