this does not make sense

bgnbfy · Veteran Member

this does not make sense

PitchBlackSS · Treasurer

sounds like a hub sensor. Check the wires going to the hub, they come loose and become corroded over time. And yes, have heard that it cant be read, some scanners cant diagnose the issue.

However, the trac off / ABS or brake light on usually dictates a bad wheel sensor or hub. The sensor is built into the hub and cant be replaced on its own. Have to replace the entire hub. But check the wires first, have seen it many times.

bgnbfy · Veteran Member

thanks...ill give it a try. but check this out when they hooked it up it said error code and now the sensor doesnt go off anymore. so where is the sensor located, front or back or both?

PitchBlackSS · Treasurer

all 4 wheels have a sensor, some scanners can pin point exactly which wheel is giving the code

twomanymontes · Moderator - Monte Hunter Lead Investigator

Well, First off, If you have a bad wheel bearing with play, like you mentioned in the other thread, that sensor could be shorting to ground when it moves causing the light to go on and off. The Sensors are built into the wheel bearings. If the bearing has been noisey [ growling] it will cause interference on the AC signal to the Electronic Brake Module and in turn cause everything from false ABS activation to a light on the dash.

Second, ABS codes are self clearing! So Unless that light is on, it will not show any codes, If your mechanic has access to a Snap on or a Tech 2 scanner, it will show him history codes and how many times it has set since it first was detected.

Repair the wheel bearing and see if the light returns.

1987ls · Veteran Member

I HATE wheel sensors!!! Change them on our oil trucks every time we do a brake job, if they last that long!

bgnbfy · Veteran Member

im really surprised they didnt do a recall on these wheel sensors considering they affect most of the monte carlos not just my yr. they are a safty issue and they go out quickly

twomanymontes · Moderator - Monte Hunter Lead Investigator

They won't recall it, because ABS is not manditory on all vehicles yet. And because it doesn't affect the service brakes when the fault is present. And it affects more than the Montes, Impalas, Regals, Malibus, Cutlasses, Basically all W-body and N-body cars.

On the Trucks where the sensors can be removed from the bearings, rust builds up betwen the sensor and the bearing, this increases the air gap betweent the tone wheel and the sensor tip and tricks the sensor into thinking the wheel is locked at low speeds.

PitchBlackSS · Treasurer

here's a good read for you, let me know if it works.

Checking your Sensors

Gib DTD · Member

If you dont notice anything wrong with the wiring, you're most likely going to have to take it to the dealer and have them run a scan on it. Some codes can only be read by the dealer, and the dealer will be able to tell you exactly which hub it is.
I hope its nothing more than a bad connection.

EDIT: Most mechanics have scanners that only read engine codes because they are the most common problems, and the can profit the most from purchasing the simplest scanner possible. An example is the mechanic who buys the $200 handheld scanner rather than GM's $10,000 code readers that will tell you everything thats wrong with any GM model.

-- Edited by Gib DTD on Tuesday 23rd of February 2010 10:14:34 AM

twomanymontes · Moderator - Monte Hunter Lead Investigator

Gib DTD wrote:

EDIT: Most mechanics have scanners that only read engine codes because they are the most common problems, and the can profit the most from purchasing the simplest scanner possible. An example is the mechanic who buys the $200 handheld scanner rather than GM's $10,000 code readers that will tell you everything thats wrong with any GM model.

-- Edited by Gib DTD on Tuesday 23rd of February 2010 10:14:34 AM

I'm not sure what scan tool runs $10K, But GM's Tech II is $5500, plus I believe the CANDi Module is another $1100, and it doesn't tell you everything that is wrong. Scan tools only give you code #'s with discription, Module and sensor information, Bi directional controls over components and programing capabilities. The Tech needs to take that information and be able to diagnose the car.

Most mechanics, myself included, own the Snap on MT-2500 or the Solus, They are as close to the factory scan tools as the manufacturers will allow. usually about 3 years behind, But they will read all the modules in the car if you have the right updates.