Hello everyone,
About 6 months ago, my dad drove through a large mud puddle (not his brightest moment) and ever since then, the abs light has been turned on. while diagnosing the problem, about 50% of the time the pc claims it is the abs and the other 50% it claims its the fuse box or some sort of sensor near the hood i never heard about.
the car has been dragged out of the mud in an unprofessional manner, maybe a few wires were disconnected by mistake. Any help would be appreciated.
So who is running this PC and what software package is it and what codes does it throw?
Sorry, I can’t see this damage over the internet. If there is damage to wires, you need to fix that before you do anything else.
I had 2 different guys running a diagnostic from 2 different pc’s:
one is a friend of mine who is just a auto-enthusiastic, and the other is the mechanic at my repair shop. they both seem to agree that its the abs module/
about the disconnected wires; I honestly don’t know, haven’t lifted/took apart the car yet to check.
I dont know what pc the mechanic is using, and my friend sent me the report from his device:
he uses a thinkcar t-wand 900 on the latest update and the codes are as following:
I don’t know what to make of it. with that many codes I am actually suprised the vehicle is turning on at all.
hope that helps
The first letter in the codes (C vs U vs P etc) refers to the computer involved with that function. Cars have multiple computers these days, the “P” computer is for the powertrain (engine & possibly transmission) for example. The P codes are probably not related to the ABS sensor problem. The U & C codes could be caused by broken wires going to the ABS wheel speed sensors.
Thank you both for the detailed reply, but just so we are on the same page, can you give me a rundown of all the parts of the abs? the mechanic insists upon calling it some sort of “package”, but I am interested in what constitutes the abs and what each part does, before i buy the whole thing.
There are quite a few codes related to the CAN bus operation. Any one of the numerous modules connected via the CAN bus on the vehicle could be causing these disruptions as well as connection issues in the CAN bus itself. I wouldn’t assume it is the ABS control module but I would be examining anything that was submerged in the mud hole as well as any wiring harnesses that may have been damaged in the extraction process.
There is a hydraulic unit that has sensors and valves and the electronic control unit that does the control and communication.
ABS specific sensors are all wired directly the the Control unit. Wheelspeed sensors, steering wheel sensor and inertial measurement. These sensors are used elsewhere in the car but are communicated from a CAN buss data line running to every other electronic control unit. Likely 9 to 15 or so of them.
All the U code errors are troubling. The ABS module might be OK but the communication buss is clearly down to several ECUs
So you think I should take it to a garage and have it cleaned again? they are just not fond of disassembling anything if they don’t already have the replacement part ready to be installed. Since they are not sure what the problem is, they might start taking shots in the dark and just replace things one by one until they get it right.
The comment above tells me that THIS comment below is not a good move
No. I think you should take it to a mechanic that isn’t just guessing. I think there are more problems than just the ABS unit and clearing codes won’t help a bit. They will just come back because it hasn’t been fixed. That’s why they HAVE error codes, so you know when it has a problem and when it has been fixed.
The thing is, I took it to another garage today, They did a free diagnostic and also found all these codes. They said they want about 400 bucks for a more in depth diagnostic and afterwards they will go over all the codes one by one and fix the problem. Obviously, for each code they tend to, the price of the repair is gonna go up, but they said they will start with the more serious codes (not with something like “roof calibration not learnt”). these is a garage which is a certified buick repair, but I am afraid the cost will be too high to break even (car costed around 8.5k a few years ago)
Sounds like these guys have underdeveloped diagnostic skills . . .
Good work takes time and costs money. You might pay $400 to this shop but save thousands in the long run. They are going about it the right way and being honest with you. That would give me a comfortable feeling.
The other shop seems like they want to throw expensive parts at the car hoping one will fix it. That will very likely cost you more and still not fix it. Some shops are ok for brake jobs but not for electronic repair.
Alright that is sound advice. Only problem is that the latter garage is also not 100% sure that the problem is the ABS either. I will keep updating this thread in hopes it helps others.
You have fault codes from several different modules all mixed into one list, this can make things confusing.
The common fault in some modules is loss of communication with brake control module, this is an indication that the ABS control module is offline.
If the scan tool can’t communicate with the ABS control module, then power supply and ground at the ABS connector must be verified. There are more steps but begin with this.
The shop that you when to today won’t complete the diagnoses for free, if they did you might return to the first shop for a cheaper repair.
It is an ABS problem, they are not going to tell you what parts need to be replaced for free. Expect to pay close to $1000 for the repair.
Suggest to look up the “anti-lock braking” article published on the online encyclopedia Wikipedia. It won’t cover your exact car’s configuration, but should prove helpful. A brief summary: the ABS computer/module constantly monitors the wheel speed (in rpm) for each of the four wheels as you drive. If they all match, that means all four wheels have good traction to the road. If one of the four doesn’t match the other three, that means that wheel has lost traction. When that happens the ABS computer will apply brake pulses to whatever wheels it thinks needs extra braking, in order to regain traction for all four wheels. The main parts are the ABS module, and the four wheel speed sensors. By reports we get here, wheel speed sensor failure is much more common than ABS module failure. You are welcome to review past posts about that topic by clicking on the forum search link, upper right this page. Car repair has become very expensive with computerized cars. Best of luck.
They did a free code check to give them a direction to go in, once they had an idea of what to expect, they determined (from experience) how much diagnostic time and cost they would need to perform a proper diagnostic… Remember the diagnostic only pays them for the check(s), repairs will be more…
Alright, went to another mechanic, said it was the ABS. replaced it and changed oils, problem solved (until next time). total cost: 320$
conclusion: knowledge is power, needed to perform a cross examination 
That’s a very good value for that amount of work, plus the price of the replacement part … suggest to give a box of donuts to the shop’s staff! Was it the ABS module? Or just a wheel speed sensor? I’m thinking for $320, it must have been just a faulty wheel speed sensor.