Diagnosing brake pedal pulse
 

What's up guys. working on my dad's 05 mountaineer awd 4.0 w/ advance trac. I dont have an abs light on but the brake pedal was pulsing whenever you brake, not just at low speeds but all the time. I have an abs scanner, but with no light showing I guess it's not throwing a code. Pads and rotors are new all the way around. Pulled #5 fuse for abs and the pulsing stopped. My question is, if its a sensor, how do I know which abs sensor is malfunctioning? Front left, front right or rear? My old man drives about an hour to work and an hour home, so I wanna get this thing fixed. Any help or input would be appreciated. Thanks.

Does your ABS scan tool allow you to monitor the wheel speed sensors real time? If so, monitor the sensors and see if one is behaving differently from the others.

-Rod

Hey thanks for the help man. I finally got a few hours to work on it, scanned it and it's throwing a c1998 code. Module calibration incomplete. So i think I gotta bring it to the dealer to get the module re-programmed. It's had the Advance Trac light on in the message center for a while now, so im hoping that will fix both the Advance Trac and the brake pulse, cause erratic brake behavior is one of the symptoms. I guess we'll see. Thanks again, I'll update after I get it back from dealer

It's possible that it will require a trip to the dealer or someone with a professional scan tool, but the calibration requires input of turning the steering wheel from lock to lock. Before scheduling that appointment, I'd recommend you try starting the truck and turning the steering wheel from lock to lock at least one time to see if that happens to clear the code C1998. The manual does not suggest that you need to start with clockwise or counter clockwise.

-Rod

Ok I will definitely try that before I bring it anywhere. Thanks again, I appreciate it. I'll let you know what happens.

Ended up getting it done by a friend of a friend who owns a shop for free (he wouldn't take any money). Took about 5 minutes. Pretty sweet deal. Module calibration took care of advance trac problem, but pedal pulse was actually front rotors. They were new, but turned out to be defective. Bought the best rotors parts store had and ceramic pads, that fixed the pulse problem. Guess the lessons of the day are you get what you pay for, and dont assume it's good just because it's new. Thanks for the advice. This forum is full of good people and good info and I really appreciate the help you guys always give. I need all of it I can get lol. Thanks. Later.

Congrats, and thank you for following up with what you found.

So "Pulled #5 fuse for abs and the pulsing stopped" was apparently in your head?

-Rod

No I drove that car a lot, braking at both high and low speeds, and the pulsing definitely stopped, or at the very least was lessened to the point where I couldn't feel it anymore. Thats why i really thought it was an abs problem like a sensor. I don't know if maybe both the rotors and the abs module contributed to the problem? I haven't even thought about that, thats a good point. I'd like to know the answer to that myself honestly.