Braking and ABS issue?

CJTCT

MEMBER
2001 TOYOTA SIENNA
6 CYL
2WD
AUTOMATIC
165,000 MILES

After recently got a replacement for the front brake pads and rotors from one brake store, found every time pressing the braking pedal always kept pulsing like ABS lock-on false triggered while driving speed more than 30-40 mile. A longer braking distance and high-risk driving, not any ABS and brake code light on. To test ABS, unplugged the cable from the ABS control unit, braking working normally. But ABS and engine check light on, speed meter not working anymore. After testing, reconnect the cable to the ABS unit, unfortunately, ABS and checking light still on showing ABS and speed sensor abnormal. Please help figure out what is wrong. ABS/speed sensor or ABS pump control unit? Really appreciate any suggestion! Josh

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi Josh,

Since it was brakes and rotors, I assume it was the front brakes. Chances are you either disconnected the wheel speed sensor or it was damaged.

First, check the sensor, wiring, connections and anything that could indicate damage. I attached a pic below of the sensor's location. If nothing is found, continue with the next step.

We have two ways of doing this. First, if you have an upper-level scan tool that can read live data for each sensor, drive the vehicle and see if the signal from the sensors are all the same. If one is lower (slower), that is where the problem is coming from.

If you don't have the scanner, then we need to check each front wheel speed sensor using a multimeter or voltmeter. Follow the directions in the following link. There is a video in it as well to help guide you.

https://www.2carpros.com/articles/abs-wheel-speed-sensor-test

Let me know the results. Also, please feel free to let me know if you have other questions.

Take care,

Joe

See pic below.

Image (Click to make bigger)