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97 Malibu V6 3.1L ABS Light Always On


AF_Dali
10-25-2008, 05:37 PM
Hello,

The ABS light of my 97 Malibu was on and off quite some time ago. It has always been on recently.

It could be the bad ABS sensors. I have the two front hub bearing with integrated ABS sensors replaced to solve the noise problem and the ABS light on problem.

After the replacement, the noise is gone but the ABS light is still on. Will the ABS light be off after the vehicle being driven for some time, just like the flate tire warning light being off only after some time of the tires being recharged (for the internal microprocessors to do the calculation or recalculation)? Or do I need to have the ABS error code cleared from the computer after the ABS sensor problem's fixed?

Are there any other cause of the ABS-Light-On, such as bad spark plug wire being the source to generate the ABS DTC code as commented by AF member cbec1999 in my another thread?

Thank you!

Scrapper
10-25-2008, 05:54 PM
try unhooking your neg side of battery cable and leave it off maybe 15 miniutes that resets your computer. if it go's off for awhile and comes back on you still have a problem.

good luck...

AF_Dali
10-25-2008, 10:18 PM
try unhooking your neg side of battery cable and leave it off maybe 15 miniutes that resets your computer. if it go's off for awhile and comes back on you still have a problem.

good luck...

Hi,

I disconnected the battery negative cable and reconnected it after 1 hour. The ABS light is still on. Is there any other way to reset the ABS error code so that the ABS light will be off, even if the ABS light will come back on if the problem is not fixed?

Any suggestions?

Thanks a lot!

Schrade
10-25-2008, 11:41 PM
Hi,

I disconnected the battery negative cable and reconnected it after 1 hour. The ABS light is still on. Is there any other way to reset the ABS error code so that the ABS light will be off, even if the ABS light will come back on if the problem is not fixed?

Any suggestions?

Thanks a lot!

Some codes do not erase by unplugging the battery.

It is possible that a spark plug wire can emit radiation which causes false trouble codes, IF IT HAS TOO MUCH RESISTANCE. Read it in Chevy shop manual, and experienced it myself '94 vette this summer. Nightmare troubleshoot uh huh.

Check all 12 spark plug wire ends for GOOD connection. If they are all good, you'll need to get a troubleshoot printout from a local shop somewhere. Might have to offer a few bucks for it.

How does it idle?

Don't necessarily go buy a set of wires either, unless you see something really wrong.

AF_Dali
10-28-2008, 03:16 PM
I had my Malibu ABS system scanned and it turned out to be the rear right ABS sensor circuit is either short or open circuit. The error code can not be cleared, thus the ABS light is still on.

Anyone has the similiar experience and how was the problem fixed? Thank you!

Schrade
10-28-2008, 05:14 PM
I had my Malibu ABS system scanned and it turned out to be the rear right ABS sensor circuit is either short or open circuit. The error code can not be cleared, thus the ABS light is still on.

Anyone has the similiar experience and how was the problem fixed? Thank you!

Got a multimeter? Power ain't gettin' to the sensor like it's supposed to, and multimeter shows it like a champ! Just like lookin' for a hole in the water hose, 'ceptin' you don't get yer fingers wet nope!!!

maxwedge
10-28-2008, 06:39 PM
The sensors are not powered, they generate a millivolt current that is sent to the brake control module, this is then interpeted as a comparative wheel speed input, if no signal at all the system assumes an open or grounded circuit. Look for approximately 1100 ohms resistance at the sensor, then trace that circiuit back to the module looking for a broken or frayed wire.

AF_Dali
10-28-2008, 06:49 PM
The sensors are not powered, they generate a millivolt current that is sent to the brake control module, this is then interpeted as a comparative wheel speed input, if no signal at all the system assumes an open or grounded circuit. Look for approximately 1100 ohms resistance at the sensor, then trace that circiuit back to the module looking for a broken or frayed wire.

Hi maxwedge:

Thanks a lot for the information. I will do some measurement and post back.

Scrapper
10-28-2008, 08:42 PM
same thing just happen today but ended up being broken down inside the module. run good on the machine before replacing module. look at this i have no ideag that it went on this thread..sorry.

AF_Dali
10-28-2008, 09:01 PM
same thing just happen today but ended up being broken down inside the module. run good on the machine before replacing module. look at this i have no ideag that it went on this thread..sorry.

Hello scrapper1:

What did the ABS scan tool tell you about the ABS error? Did it say its a faliure of the ABS sensor circuit or a failure of the ABS Control Module?

This will help me further diagnose the problem of my Malibu.

Thank you!

maxwedge
10-29-2008, 02:36 PM
Careful here with abs codes, some scanners will give false codes that look like a failed ebcm , when looking closer at wheel speed inputs the actual culprit turns out to be a sensor, had this happen on a 98 GM car using an Snap On mt2500 scanner.

AD2BU
11-03-2008, 05:24 AM
On my 98, the problem turned out to be the wire harness connector. Replaced the wire harness connector and about one foot of wire. The wire harness is a common issue on these ABS systems according to one mechanic I spoke with. Good luck hunting this down.

AF_Dali
11-03-2008, 10:22 AM
On my 98, the problem turned out to be the wire harness connector. Replaced the wire harness connector and about one foot of wire. The wire harness is a common issue on these ABS systems according to one mechanic I spoke with. Good luck hunting this down.

Hello AD2BU:

did the wire harness or connector problem happen on the front wheel or the rear wheel, and which side?

Please let me know, thank you!

AF_Dali
11-06-2008, 06:40 PM
The sensors are not powered, they generate a millivolt current that is sent to the brake control module, this is then interpeted as a comparative wheel speed input, if no signal at all the system assumes an open or grounded circuit. Look for approximately 1100 ohms resistance at the sensor, then trace that circiuit back to the module looking for a broken or frayed wire.
Hello maxwedge:

I did the measurement, the resistance of the ABS sensor at the Right Rear wheel is about 1.1-1.6kOhm. I compared it with a new part, they are pretty close. Now the question is how i should track down this resistance along the wire harness up the the EBCM unit? I've had the connectors cleaned.

Any suggestions? Thanks a lot!

maxwedge
11-06-2008, 07:06 PM
Keep in mind even though the sensor checks out it can still be bad. find the appropriate wires at the ebcm and check for continuity there. A scan with a abs scanner will pinpoint the suspect sensor, during a road test the wheel speed inputs can be monitored to see if one drops out or has no input.

AF_Dali
11-06-2008, 07:35 PM
Keep in mind even though the sensor checks out it can still be bad. find the appropriate wires at the ebcm and check for continuity there. A scan with a abs scanner will pinpoint the suspect sensor, during a road test the wheel speed inputs can be monitored to see if one drops out or has no input.

Hi maxwedge:

I kind of found the location of the EBCM, which is located in the inner splash board of the driver's side front wheel. Should I remove the EBCM unit then measure the connectors in the box that holding the EBCM unit?

Please advise. Thank you!

maxwedge
11-07-2008, 09:14 AM
This can be a tough job to pinpoint the 2 wires for each wheel sensor and check continiuty in the harness back to the sensor, you must use a long jumper, of course, to each sensor wire.

AF_Dali
11-07-2008, 10:28 AM
This can be a tough job to pinpoint the 2 wires for each wheel sensor and check continiuty in the harness back to the sensor, you must use a long jumper, of course, to each sensor wire.

Hi maxwedge:

Glad to hear from you!

Would it be feasible to measure the resistance between two connectors at the bracket box of the EBCM Unit? If the resistance of 4 pairs of connectors to the 4 ABS sensors are close the the resistance of the sensors, then the connectivity might be ok, otherwise there is a open or short.

Please advise, thank you!

maxwedge
11-07-2008, 02:10 PM
The resistance will be higher of course, but I don't know how much over that length of harness, but if is way out of whack you know there is an issue in that circuit.

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