Strange ABS Issues - Module Problem?

[md1twal3]

I'm not sure if these issues are related to the same root cause but may be. For a very long time, I have had the ABS activate on every stop regardless of pavement conditions. Seems its one or two light pulsations and that's it. This never sets a code.

However, I do periodically get codes C1233 and C1234 to set together. It's never one or the other, always both. Conditions that trigger these codes include initial warm up under extreme cold conditions. And, very agressive acceleration. I can duplicate the light on and code setting every time when accelerating hard.

Both front hubs were replaced with Timken brand hubs for growling about a year ago and I know for sure the every stop activation was also occuring prior. Don't recall the codes setting though.

The only other thing I notice is that the pedal seems to fade to a certain point when stopped and manually pumping the brakes doesn't firm it up; the pedal will still fade the same as without pumping the brakes.

Anybody seen this or have ideas????

 

[md1twal3]

I figured it out...the front wheels are coming off the ground when I hit it hard. ;-)

Seriously though...anybody?

 

[joegr]

Probably a wiring harness issue. The front right corner seems to be a common place for this.

 

[md1twal3]

I suspect a possible wiring issue and since you mention the RF, I'm even more suspicious. Last winter, someone backed into the RF corner and exposed the wire core on several wires in that large harness that sits near the corner of the core support. I spent hours combing through them all and repairing the damage. It's possible I missed something and now the elements have brought it to light.

That could be the cause of the codes but the light ABS application at every stop has been occuring far longer than that.

I'll take a look in my electrical manual to identify the circuit and will do some testing. Any chance anyone could provide the factory troubleshooting steps for C1233 & C1234?

 

[joegr]

http://deneau.info/ls/s6x~us~en~file=s6x69003.htm~gen~ref.htm

 

[md1twal3]

http://deneau.info/ls/s6x~us~en~file=s6x69003.htm~gen~ref.htm

Excellent, Thanks much! Quick clarification. The link is for an 06 LS, mine is a 00. Any concerns with that?

 

[joegr]

Excellent, Thanks much! Quick clarification. The link is for an 06 LS, mine is a 00. Any concerns with that?

Sorry, I was thinking you had an 03 for some reason. The gen II stuff may not match very well with the gen I on ABS. I don't know how much they changed on that.

 

[jarrett88]

I'm not sure if you have figured out the problem or if its the module, but I remember i had an ABS module issue w/ my last car and I just pulled the power to the module, not sure how to do it in the LS but you can always do that.

 

[md1twal3]

I'm not sure if you have figured out the problem or if its the module, but I remember i had an ABS module issue w/ my last car and I just pulled the power to the module, not sure how to do it in the LS but you can always do that.

I appreciate that but I prefer to have my ABS functional so figuring this out is needed.

 

[md1twal3]

Sorry, I was thinking you had an 03 for some reason. The gen II stuff may not match very well with the gen I on ABS. I don't know how much they changed on that.

I'll do some comparison from the circuit testing pin outs in the link you sent vs. the pinout descriptions in ,y factory 00 electrical manual to see if they match up. Maybe between the two resources, I can figure this out.

 

[LS_Monk]

I have the same problem. (always abs pulsing during stopping, no light, but felt in the peddle) As of 2 weeks it has gotten worse too. When i step on the gas to speed up the traction light, abs, and ebrake come on. It clears everytime the key is turned off.

I hooked up my scanner to see what the abs is doing when i am driving. well both front spike up during acceleration. ex: rears are doing 80kph and i step on it it spikes to 200kph. 1 side was changed with motocraft wheel bearing a year ago and the other side SKF. I have changed 1 wheel speed sensor and still for boh sides.

I am guessing the abs module is the problem. I think i might go to the junk yard and pull a used one from a 2001 and try that. I know it says it need to be programmed but Im hoping a used from same year will work with out issues.

 

[md1twal3]

Please keep this link updated LS Monk and I'll do the same with my diagnostic efforts. I'm glad (and not glad) that someone else is experiencing the issue.

 

[LS_Monk]

Im leaving for florida for a week and a half and the day I return I think im gonna open up the module and look for anything that came un-soldered

 

[LS_Monk]

Well no need for looking into the ABS module. IT WAS THE ALTENATOR. I tested it before when it all started to act up, and it was woking great. Must have been a load test when driving that had it start to fail. Last time the alenator failed it was doing this. All I still have is the occasional abs pulsing the brake pedal every once and a while when stoppping. BUT NO LIGHTS ON NOW. I have replaced the rear axles and front wheel bearings since this litle pulse has stared (2years ago) so it may be the abs module. Maybe one day i will tare into it and see, but for now its liveable