Service ABS/TC comes on at times, hit reset and things are fine for a while. Could be a day, week, or month. Then it comes back just whenever it wants to. Sometimes when I first start the car, sometimes when I get on it hard, seems anything or nothing can trigger it. Any ideas???

BTW it's a 2000 A4 coupe.

Thanks!

Dan

 

You need to read the codes and post them here. Generally the computers will tell you what's wrong.

 

I am currently experiencing the same thing. I've read a variety of posts and seems a computer part is often the culprit....and an expensive one at that. Just about all of the posts I've read also said that continuing to drive won't cause further problems if you can tolerate the DIC notices.

Do a search on this topic and you can probably find the post that explained how to get the codes using the DIC if you don't have a tuner/code reader to plug in and get them.

 

with the key in the on position, but the engine not running
push and release the reset button until all messages cleared
next push and HOLD button #4
next push and release button #1 four times while holding button #4
When first engaged the on-board diagnostics go into an "automatic" mode which shows all parameters: PCM-TCS-RTD-BCM-IPC-radio-HVAC-LDCM-RDCM-SCM-RFA. If there are no problems, you will see "no more codes" on the ICP display. The computer will show two kinds of codes, "current" and "history," designated "C" or "H". A current code indicates a malfunction is present in the system whose module is displaying data. A history code indicates a past problem. When the screen displays "manual diagnostics," select the desired module by pressing the "options" button to go forward or the "trip" button to go back. Press "gages" to go forward or "fuel" to go back. To exit the diagnostic mode at any time, press "E/M".
If you want to erase or "clear" codes, press .""reset

NOW, tell us what codes you have ???

 

Thanks guys, I'll check the codes in a couple of days and let you know.

Dan

 

I have a superchips programmer. I've been getting the same DIC indicators. I plugged in the programmer and it didn't pick up on any codes. Of course, the DIC wasn't showing it at the time but it rarely does at start up. Grrrrr!!!

 

OK, here are the codes!!


10 PCM P1431H

28 TCS C1226H

28 TCS C1243H

AO-LDCM B2264H

BO-RFA U1096H

B0-RFA U1064H

BO-RFA U1016H

BO-RFA C2105H

Thanks to all!

Dan

 

I had even more codes but ALL were followed by an H. So that would indicate in both Dan's and my case those are old codes, right? If so, what else could cause this? I have a feeling this is a computer module that's gonna cost in the low 4 figure range.

 

Dan, the C1243 and C1226 are the issue.

C1243 is BPMV Pump Motor Stalled. For this, I would first take a look at the ground G101...detailed in the thread below post #1:

http://forums.corvetteforum.com/c5-t...o_threadsearch

C1226 is for the RF Excessive Wheel Spin Variation. Take a look at wheel speed sensor harness on the RF wheel.


The link I provided is full of troubleshooting for these exact issues.

 

for C1243...try this from another forum member:
Nothing seemed to make a difference until I ran across the thread about a member who was clearing the code while driving and then slamming on the brakes to activate the ABS. I know when the car is started the system turns the ABS pump on and off and if the voltage readback is not high enough the code C 1243 is set and you get the messages. Since I do not have the interface connector for the EBCM I pulled the module away from the pump section. I measured the resistance of the pump motor from pin number 8 ((from left to right) (it is the first pin on the right hand connector))to the frame ground and it was in spec according to the manual. In my job we also use different size pumps for pressure and vaccum. When a pump is new or has been rebuilt it requires some break in period. If a pump has been used and off for some period of time it will also draw more current due to sediment build up and not being exercised. With this in mind I pushed a wire into pin 8 and ran it over close to the positve post of the battery so I could exercise the pump manualy. The pump came on the first time I touched the positive post but sounded sluggish. I exercised the pump about 6 more times for about 15 to 20 seconds at a time. I put the EBCM back on the pump section cleared the codes and so far the car has been running for one week now with only one message the first day after this procedure that message cleared on the next start by itself. If you try this use a heavy gauge wire and be aware the wire may get warm as you touch the battery. The pumps on these ABS units are most likely not broken in since they hardly run durring the life of the car.

for C1226... wheel speed sensors Code C1226 indicate that one of the wheel speed sensors is either sending a bad signal or no signal. Start by checking the connections. The wheel speed sensors are integrated into the wheel bearing/hub assembly pictured below. The wire coming out of the back is the connection for the wheel speed sensors. Verify that the connector are not broken, damaged, or corroded in any way. Pay particular attention to the female end.

The wire coming out of the wheel speed sensor connects to and 18" jumper harness, then to the main harness. It is very common for people to have a weak female pin in one of those connections. If all of that checks out good, swap the jumper harness from side to side. For example if the left front is bad, swap it over to the right front. And install the good one from the right front to the left.
side. Then clear the trouble code. If the trouble code is now on the right side, you know the wire harness is the problem. If the code is still on the left side after swapping the jumper harnesses, you know the problem is inside the wheel speed sensors.
If all the wires check out good, it's time to take a trip to Auto Zone for a new set of bearings. You can buy replacement AC Delco bearing from your dealer if you want to, or get the exact same bearing in a different box for half the price (~$150) from Auto Zone, you decide. The bearings should be replaced in axel sets, so if your left front is bad, you have to replace the right front too. While you’re at it, this is a good time to upgrade the lug studs and add spindle ducts.

 

Check battery terminals and connections. A new battery fixed my intermittant ABS/TC codes. Then a few months later I started getting all kinds of wacky codes and loss of driver side door panel control/lights. Checked my battery connections, a bit loose (after the cold months, or just me), and cured these problems. Now I still have one more wack problem with drivers side door panel control to solve.

 

I'm confused about one thing now....I thought codes that were followed by H are historical codes and if they are followed by a C are current issue codes. ALL of Dan's codes (and mine) are followed by an H.

Dan....hope you don't mind me piggy backing. Just have exact same issue going on.

 

That's correct, but "history" could be 5 minutes ago. With an intermittent issue, that's what you would expect.

 

I was kinda thinking the same thing about the H's. And you're not piggy backing! All input is a help to us all.

Dan

 

It was my understanding a new code has a C but once resolved, it's stored with the H. If that same issue arises again, it wouldn't revert back to a C?

Dan....since they're all historical codes, have you tried clearing them as described above? I think I'll do that today and see if they pop back up as current.

 

Funny you say that. I cleared all of them about an hour ago before I read this post and we're doing a road trip tomorrow so I'll see what pops up next week.

Dan

 

Well, I cleared the codes before driving to work. Popped up again and had the same codes, still followed by an H. Guess that indication doesn't mean much. Oh, well. Moving on to checking the connections and grounds. Let me know how your's works out.

 

I spent 6 months chasing this when a/c vent doors starting acting up then a delay before radio and a/c would come on maybe as long as a minute/new $70. Ignition switch electrical part fixed everything

 

Dan,

Start with the easy stuff first - Battery and grounds

If I remember correctly - Check grounds 103 (on driver side mid-way between headlight and wiper) and ground 108 which is right by the battery

Next time it rains, take the car to somewhere safe to lock-up the brakes so your ABS engages and you exercise your ABS motor (I would suggest a slightly wet grassy area because it is easier on the tires). Lock-up the brakes about 5 times and be sure to clear the code before each attempt.

Report back to us - Code 1243 can be a tough one to resolve

 

Well, I remembered that I recently took apart the center console when I had a shifter problem. So on the way homethis morning I pulled over, turned off ignition and popped up the TCS/AH button panel. I unplugged the switch, checked posts (all clean) and plugged it back in. I drove about 3 more miles with no indications. It's been coming on almost immediately but I'll drive a bit longer later today after I get some sleep.

UPDATE: No codes today. Woo-hoo!! Guess I solved my problem without even getting out of the driver's seat.