ABS and brake light comes on and stays on over bumps

[Bread Van]

yeah, I saw your posts on this. I've just gotten used the lights. Thought about sending the module in but don't daily drive the van and just sorta accepted the idiot lights.

Now after reading those posts and the links to the S10 posts I hope to try this repair...now just need time. Got back from a vacation and I'm kinda used to relaxing

[ccookie66]

Yeah. Whenever mine goes over humps, bumps, or anything else the light comes on. Sometimes its on all the time. Its done it for 15 years. I think the ABS system still works, I don't know.

[Rolling_Rock]

Its a real EASY fix- the hardest part is taking the module off the van with the limited access to the t20 bolts

HOW TO video HERE:

http://www.youtube.com/watch?v=P_6Sk7-fm0I

[ccookie66]

YES!!! Thanks for the link to the fix. Rolling_Rock, I'm gonna hug you.

[96 astro]

Most times when I start my van the ABS light and brake light come on, then go off, as they should.

However within a short distance both will come on at the same time. I have seen this happen enough to realize that is always happens after going over a bump. Once the lights come on, they stay on.

I figured I had a front wheel sensor issue, but this is making me think I might just have a bad connection somewhere.

Any obvious locations I should be investigating. Any help is appreciated.

this is the same problem as i was having but only the abs light came on
but now fitted a new n/s/f sensor and problem solved ..

steve

[Bread Van]

I finally got around to trying the resolder fix but only with partial success. I no longer have the "brake" light illuminated but the ABS light comes on immediately after startup. I don't have a proper scanner to read the brake system codes so I just tried the resolder on a whim.

[Corsemoto]

Is the fuse good?

Could be the abs pump, test resistance (1-5 ohms) at the pump connector, if it's open the wires are probably bad or corroded and wires/connector can be resolderd at brushes. Can also check to see if pump cycles by supplying 12v directly at the connector.

ABS Indicator
The IPC illuminates the ABS indicator when the following occurs:
The Electronic Brake Control Module (EBCM) detects an ABS-disabling malfunction. The IPC receives a class 2 message from the EBCM requesting illumination.
The IPC performs the bulb check.
The IPC detects a loss of class 2 communications with the EBCM.

[Bread Van]

Pasting this from another thread since it relates to my issue. Thanks again Corse. Unfortunately I will not have time to dig any deeper for another couple weeks due to work and a trip. Taking the van to Mesa Verde, Cedar Mesa and Valley of the Ancients for the long holiday weekend....then back to work, work, work.

Who repaired your ebcm?

If the ABS light is coming on after driving around for a bit, I would talk to your ebcm repair provider as according to http://www.modulemaster.com/en/wizard/kh_325/after_moving.php if the ABS light is coming on after driving van then the fault is internal to the ebcm.

If the ABS light turns on only after the vehicle starts moving, this would indicate an internal fault in the ABS module.

For a fee, you may have your module scanned for error codes by your dealer or a certified repair shop. Or send your module to ModuleMaster and we will scan it for free. If there's nothing wrong with it, all you will owe is the return shipping.

If the ABS light comes on when van starts http://www.modulemaster.com/en/wizard/kh_325/after_starting.php

If the ABS light turns on immediately after starting the engine, you either have an open wheel speed sensor, or the ABS module is not getting power. Check the 50A ABS fuse in the engine compartment as well as the ABS fuse under the dash. If the fuses are good and power is getting to the module, check each wheel sensor as follows.

1) Jack up the front of the vehicle until both front wheels are off the ground.

2) Find the sensor connector inside the front-right wheel well, and disconnect it.

3) Set your multimeter on AC volts, and connect the probes to the connector leading to the sensor.

4) Spin the tire by hand while observing the multimeter. You should get 180-250 milivolts AC. If not, check the resistance of the sensor. It should be 600-2400 ohms. If you're reading infinite resistance (open circuit), or very low reistance (a short), the sensor is bad.

5) If you are reading a fluctuating voltage from the sensor, but it is not within the range indicated, you probably have a dirty sensor. Remove the tire and locate the sensor mounted within the wheel hub. Remove the sensor and thoroughly clean any corrosion from the aluminum mating surface as well as the sensor's mating surface. Reinstall sensor and tire, then measure voltage again.

6) Repeat the same process for the front-left sensor. Keep in mind that a discrepancy in voltage between the two front sensors may also indicate a dirty sensor- even if the voltage is within the specified range. In this case, remove and clean both sensors.

7) Drive the vehicle and perform a brake test. If the problem persists, check the rear sensor connector for corrosion, although this rarely occurs.

I was told by the shop that repaired my ebcm that when they are bad can incorrectly show fault codes for wheel speed sensors. Mine did which wasn't the case once the module was repaired. Sounds like they might need to re-repair your module.

For what it's worth, the rear wheel speed sensor is a vss sensor located on the transmission (rwd) and transfer case (awd).

Add'l info:

https://www.astrosafari.com/viewtopic.php?f=45&t=13496

The above post came from this thread:
viewtopic.php?f=45&t=16517

[Corsemoto]

Lucky you, enjoy your trip and post some photos when you get back.

[Bread Van]

So I took a quick look at fuse(s). The one under the hood is good. I couldn't find a location for an ABS fuse in the box by the brake pedal. Am I missing something?

Also, my van has two sensor near the output to the rear driveshaft. One on the passenger side and one on driver's side. Which one would be the VSS that caries the signal for the ABS? My speedometer always works and I thought that signal came from the rear VSS, so I basically assumed that VSS is all good.

I'll have to wait to check the voltage on the front sensors.