I hope this is something I can fix! My 01 MDX(Touring) anti-lock brakes(ABS) are automatically engaging whenever I slowing or am about to come to a complete stop, regardless of weather. It is definitely a hazardous situation.

It started when I "stupidly" had put the MDX in 4-Low while attempting to trailer a heavy load. The torque of trying to move said trailer caused the engine to "pop" out of gear. I was able to get it back in gear fairly easily, but now have the ABS issue.

The ABS always engages when I am slowing down & about come to a complete stop or if I am traveling very slow (ie.sitting in traffic, rush hour). The brakes will release if I pump them, or when I start to accelerate.

And what's really strange, but good I guess, is the ABS system seems to work when its suppose to(in slippery conditions).

I have read that it could be a faulty sensor, but the ABS system seems to operate correctly when hazardous conditions are in play. I am hoping someone has some advice on things I might be able to do.

 

I have an 01 and I think you might be referring to the "feature" acura has built in that when slowing the transmission downshifts which feels like the car has just applied additional braking. It has but in the form of a transmission downshift not the brakes. If that is what is happening, lucky us-- it's a "feature". If I use the brakes going downhill it will downshift. If I want to coast in the highest gear for the remaining hill segment then I shift to neutral then back to D5 and you are back in 5th gear. That or accelerate to upshift which usually is not preferable going down hill.

 

If the abs is engaging during a slow stop there is usually 1 of two possible problems. The abs control unit is checking the system constantly for faults. The main fault the system looks for is the resistance value of each sensor. It does this by monitoring voltage values produced. The sensor should be inside a given range or the abs light will come on. I cannot remember the exact resistance range for the sensors on your mdx. But I will use random numbers as an example 10-100 ohms. ( in reality the resistance values will be much higher ). If 3 of the sensors are at roughly 11 ohms and the 4th is at 99 ohms the sensors all fall into the correct range. However the computer will see a large voltage gap and think the sensor with 99 ohms is slipping. There is no code set, but the system is still malfunctioning. Check the resistance of all the sensors. If one of the sensors is way off from the others this might be the problem. The other possibility is a chipped, wobbly, of really dirty reluctor ring. The reluctor ring is the toothed gear the sensor reads. This ring is what produced the magnetic field change inside the wheel sensor. If a tooth is chipped or broken it can cause the same issue. The system should throw a code for this problem. However from experience I can tell you the reluctor ring has to be really messed up to throw a code. There are some other reasons this can happen also. However 80% of the time your abs problem is caused by the issues I mentioned

Drew

http://www.pitshopgarage.com