Intermittent ABS/RSS Problem

[Cadillac Jim]

I think Chris didn't know who I was, and assumed that I was probably a typical Caddy owner that never looked under the hood. I have devastatingly sharp macrophotographs of the connector on the EBTCM but think that this is really a dealer job that needs the connector breakouts and wiring harness diagnosis special tools, Goodwrench training, experience, and manuals that I don't have. In point of fact, I have factored in struts and shocks in my estimated cost of maintenance over the next few years, as well as the transmission - but Chris says that the transmissions "are usually good." I have no data on my rear knuckles/ball joints, though. And, GM Customer Relations believes that it's in the harness, after talking to my mechanic.

I just heard from my dealer and the *right* mechanic has it and will start in after lunch. That's good news, because my memories of the car business tell me that if he thought that the job was really tough or open-ended, he would have scheduled it for the last job of the day. Oh, maybe he did...

[rockfangd]

I would never even consider removing the complete harness. If you have a wiring diagram for the EBTCM you can test continuity on each wire and once you have found the broken or damaged wire(s) you can make the repair. although the harness runs to the rear I highly doubt it would be toward the rear. If anything the problem should be between the underhood electrical panel and the Brake module. One would hope to see something obvious like pinched harness between the trans or something

[Cadillac Jim]

I would never even consider removing the complete harness. If you have a wiring diagram for the EBTCM you can test continuity on each wire and once you have found the broken or damaged wire(s) you can make the repair. although the harness runs to the rear I highly doubt it would be toward the rear. If anything the problem should be between the under-hood electrical panel and the Brake module. One would hope to see something obvious like pinched harness between the trans or something

I thoroguhly agree, which is why my mechanic sought out a Goodwrench tech that he trusted to know how to use the connector breakouts and work with this type of problem - vastly complicated by the fact that it is intermittent. The option presented to us was to buy the harness for $2K++ and install it under the hood and splice it at the feed-throughs, tear apart the body and put it clear through to the PZM and such, or scrap the car. My mechanic added the option you suggest.

The problem is that I have seen too many Goodwrench techs that would simply follow the codes and start replacing expensive modules and sensors without fixing the problem, and at the end of the day they would either attack the root problem or give up, and I would have thousands of dollars wasted on parts and labor that didn't fix the problem. I have more than good reason to believe that the tech that always got my car at my old dealer was one of those guys, good at his work but not really ready for intractable intermittent electrical problems, - and he has been trying to get me out of that car for ten years, and this would be his last and best chance.

Replacing part or all of the harness may or may not be on the table. We will have a hard diagnosis today in all likelihood, so I'll have the facts and make my decisions in the morning.

[Cadillac Jim]

The car was ready today. The tech drove it home last night and back to work this morning, with no codes and the car not having an ABS or TC "event" other than those intended for testing purposes. He noticed an occasional light engine miss, which was probably some bad gas I got a week ago but have not yet cleared. It's minor and there is no P0300 code so I wanted to get the ABS/TCM fixed first.

But, when he put it through the car wash this afternoon, several spurious codes came up, including the P1604 that was the key to the ABS/TCM intermittent problem. The tech, who normally does warranty work on new cars, freaked out and apparently went to his service manager. The result was a high-energy phone call to my home phone; I was on the road trying to get to a consulting job, stuck in traffic. The tech called my cell phone; while we were talking my wife left me voice mail that GM had called and my car wasn't safe to drive and she didn't want me driving it anymore.

The tech had a key phrase that he kept repeating that was not consistent with his speech or background: "We Do Not Do Restoration Work." On the invoice, he (or the service manager) asserted that "Customer interested in restoration type of work" which was news to me; I was taking a meticulously maintained car that I bought new and have been using as a daily driver ever since for a Goodwrench repair. I will repeat here the key paragraph that the tech, or service manager, left on the invoice.

Checked out for customer, possible harness, value of repair exceeds value of car. Customer interested in restoration type of work, doesn't want to pay dealership rates. Will take to outside mechanic for further repairs. Please note we do not do restoration type work at our facility. Customer understands this from phone conversation.

The invoice; the tech comment in writing is in the middle of the page under the label PARTS:

Note that the car drove fine in the long drive home, while I deliberately provoked the EBTCM in every safe, legal and prudent manner that presented itself, although final judgement awaits a couple of months of driving. Your comments are welcome.

[Bruce Nunnally]

Someone writing on wikipedia defined Automobile restoration as the process of repairing the degraded aspect of a car to return it to an overall "authentic" condition.

Auto Repair on the other hand, is the process of diagnosing, correcting, and returning to service. I hardly think that what you were asking them to do qualifies as restoration.

[Cadillac Jim]

I was hoping to her from Bruce and other serious car people here; than you Bruce.

The tech was brilliant and enthusiastic, and went far beyond the call of duty. Clearly he liked my car very much and respected it. He asked where the EBTCM had come from, and I told him that some dealer had bought a bunch of them and had been selling them online for years, and that it was an AC/Delco, not an aftermarket or reman. He pointed out that a new EBTCM must be programmed or it won't function when simply installed; I commented that they had probably done before shipment that to prevent comebacks. I also verified that it was matched to my 1997 ETC by part number (I believe that they wanted my VIN before shipment; I don't recall). I got the part number from one of the GM parts online vendors, crossed over from my VIN, and thereafter went by part number. I have a photograph I took last week that shows the part number on the new module, 16263319. That matches the part number on my old EBTCM.

He cleaned the EBTCM connector, checked the insertion force on each pin on both connectors, applied cleaner and something that enhanced contact. I don't know if he sealed it or not. He drove the car home last night and back to work, at my suggestion and with my permission.

He noticed a light miss I've had since last week and looked at the plug wires, and wanted to know if I wanted him to look into it; I deferred, knowing that I could get rid of a bad-gas miss by a nice lead-foot tour down the freeway for a little while, and perhaps some Techroline - not worth a Goodwrench technician's time. He probably checked and may have reprogrammed the EBTCM with the Tech II. I suspect that he poked completely through all the modules in my car with a Tech II because I have to resynchronize my fob now. That should take all of ten seconds tomorrow morning as I get into the car. Note that the invoice shows that my car passed a GM Multi-Point Inspection with no faults.

Then, he went to the service counter to do the paperwork to release the car.

Interpretation of events is not something I will do now. I would like to hear from others. PM me if you have a sensitive question, like who the dealership is.

I refuse to accept inputs like he above quote in my thinking about my car. My current position is that the car seems to be totally repaired and to have absolutely no problems. If the problem returns, I do know that I may be looking at the wiring harness and we have researched the replacement alternative adequately. I think that the HISTORY codes I saw on the car when I started it spurious car-wash codes.

Time will tell. My mechanic and I will decide together what course to take if I do find that the ABS/TCS problem recurs.

In the meantime, my wife wants a CTS Coupe; I pointed out that these are close to $50K in trim that she and I would want. A bit of a browse on the KBB find-a-used-car pages did turn up a 2008 CTS-V six-speed manual with 65,000 miles for $22K, though. It's all I can to not go drive over and write a check, but I don't have garage space for it with my existing two cars an a motorcycle. MG Mitten? When my wife started chanting "Car-FAX! Car-FAX!" I felt I had her support. But no, not unless my plan of four more years of 200,000 miles on my car falls through. Bruce's used STS-V has me drooling, too.

[Texas Jim]

Just a quick comment here about the "V"...

The 6 speed automatics that they are putting in them now are fantastic...

They seem to just KNOW the right gear to be in at all times and don't do the HUNTING back and forth from one gear to the other, like a lot of the newer auto transmissions do.

Just saying...

[Cadillac Jim]

The whole idea of changing cars awaits more time with the 1997 ETC. The CTS-V that I found probably had the price it did because it did not have an automatic. I would rather have an automatic that minds my fuel economy and protects my engine and leaves my hand free to deal with steering etc. etc. etc. but I am absolutely no stranger to manual shift and have had a manual transmission on every car that I have ever had when I had a choice. I would do it again for affordability. But, if I do see two essentially identical cars, one with manual and the other with automatic, I will take the automatic, in a Cadillac V-Series.

[Cadillac Jim]

I drove the car today in heavy traffic and at some time during the day the car threw a P1604 code that remained as HISTORY. It must have been very quick because I never saw a light. That means to me that there is indeed an intermittent in the wiring harness.

I had to reprogram the fob; the Goodwrench tech apparently reset a lot of things while he was going through my car. Apparently he understood that he was probably going to be getting it from now on. When we last talked, I encouraged him to make a bid on installing a new wiring harness and told him I knew where to get one but he had apparently already decided that I wasn't going to go for that and wasn't open to suggestion; traffic moved, and a cop motioned for me to get off the phone; the rest is history.

I've put the car up for sale on Caddyinfo. See

http://caddyinfo.ipbhost.com/index.php?showtopic=38918&view=findpost&p=191469

I've found several CTS-V cars within driving distance. I'm interested in one of these cars:

• CTS-V or STS-V in the under $30K range.
• CTS with DI V6 in the under $25K range.

I'm not too particular about mileage. I'm interested in condition and age. I *will* do a CarFAX. I will buy a plane ticket to drive and possibly buy the right car.

[BodybyFisher]

Good Luck Jim

[KHE]

Why get rid of the car due to an intermittent code?

[Cadillac Jim]

Twice before the TC/ABS lights gradually became more and more frequent until I had driveability problems with the brakes and taking off in second gear. The first time I changed the EBTCM and it stopped for months, then gradually came back. Last week the problem was constant once the car was fully hot (it doesn't usually happen when the car is cold) meaning that the EBTCM-is-down popping brakes and no-low-gear were constant. A Goodwrench tech cleared the problem by doing a thorough check and cleaning of the EBTCM connector, and the car drove fine, but a momentary P1604 code was thrown while he was washing the car to release it from the dealer.

The reason that I took it to a dealer is that my mechanic, who has been working with me on this problem for some time (see beginning of this thread) called GM and they told him that it probably needed a new main wiring harness. The Goodwrench tech concurs. The wiring harness is about $2K discount (and hard to get, but I found four with help from Caddyinfo) but it is also expensive, a 10-15 hour job, more than R&R the engine. It goes all the way to the PZM and such behind the back seat.

I had planned to do that and continue to drive the car, but "Plan B" looking around revealed that I can get a CTS-V for $22K to $25K, there are lots of them out there in that price range, and now I have big eyes for that car, or perhaps an STS-V. So, the ETC is now surplus, with the harness and installation cost at about the trade-in value of the car. So, why wait two or three weeks while the harness comes in and my mechanic installs it to trade it in for about the bill for doing that? Also, getting a dealer to take that old a car in trade at KBB wholesale isn't likely. Selling it at KBB "Private Party" prices would net me about $1.2K over the bill, if and when I could get the price.

I have started the process of gathering the funds for the CTS-V, which will come together late next week. When it does, I'm hours away from a clean title on a CTS-V which may already be in my garage. I hope that I have another home for my ETC by then and don't have to park it out in the dew and rain at night.

[Texas Jim]

Good luck Jim, on a quick sale of the ETC...

[Cadillac Jim]

I have sufficient flexibility with the ETC to be confident in a schedule. My current options are

• Buy the wiring harness and have my mechanic install it. Then, I can trade it, sell it, or drive it. This may become Plan A after I talk to him, probably today, but may not be until Monday.
• Sell or trade it, whichever comes first.
• Ask my mechanic to use his connections to find a home for the ETC.
• Shop it around at the local recycling yards.

If I do find a CTS-V, STS-V oir other car that I like, get it home and the ETC isn't sold, I try the last two options. If someone buys it, great for them and great for me.

Do you have a handle on a CTS-V or STS-V in the Dallas-Ft. Worth area? Hook me up!

[KHE]

Is there a reason the existing wiring harness can't be repaired? Seems like a lot of work (and expense) to replace the entire harness when it is probably one circuit that is causing the issue.

What happens if the mechanic replaces the harness and the problem still exists? I wonder what a junkyard would charge for a harness?

[Cadillac Jim]

My mechanic, who has been chasing this problem with me since July 2010 and who changed the EBTCM at one point, called GM after it gradually got worse over a period of months and called GM about my car. After fully discussing things, GM said that they believed that the problem was in intermittent short circuits or open circuits in the wiring harness and that they had see a few cases like mine, and that the solution was replacement of the wiring harness. He doesn't have the Goodwrench connector breakouts to do a wiring harness test-and-repair procedure so he recommended that I take it to a dealer. He made some inquiries and found a really good Goodwrench tech; unfortunately this fellow works at the same Cadillac dealer that has been trying to get me out of my ETC for almost ten years.

The tech verified that the problem was in the EBTCM connector and fixed it by thoroughly testing, reconditioning, and reconnecting the EBTCM connector. Then he put it through the dealership's car wash to prepare the car for delivery, and the same codes came back, although they were just intermittent and showed as HISTORY codes.

My mechanic's advice is to just drive the car for a couple of months and see if the problem comes back before I buy a wiring harness. That makes the most sense to me. On the other hand, if I run across an irresistible CTS-V or STS-V, I'm ready to move. I'll leave the for-sale posts up.

[Cadillac Jim]

Is there a reason the existing wiring harness can't be repaired? Seems like a lot of work (and expense) to replace the entire harness when it is probably one circuit that is causing the issue.

What happens if the mechanic replaces the harness and the problem still exists? I wonder what a junkyard would charge for a harness?

Both are good questions. If you look at all the posts in this year-old thread, water from a car wash or road puddle causes the problem, but this one can get worse until you have driveability problems. Every single code can be traced to a wire that goes through the EBTCM connector, but the connector itself has been thoroughly reconditioned by a Goodwrench tech, who also agrees that the problem is due to a "probable" harness problem.

If the problem recurs after the harness is changed, the next line of defense would be yet another EBTCM module. The Goodwrench tech didn't see the EBTCM module as broken, though.

Why can't the harness itself be repaired? Well, that is what we wanted to do when we took the car to a GM dealer. But, the GM procedure calls for replacement of the wiring harness in this case, probably because the problem is intermittent and thus practically impossible to troubleshoot by checking individual wires in the shop.

The whole thing may have begun when I had the car detailed several years ago, and they power-washed the car from underneath. This isn't a rust-belt car and didn't need that, but ever since then I have had scads of spurious codes whenever I go to a car wash that all clear by the next morning and don't come back. I'm coming to believe that power-washing a car from underneath (or under the hood) probably destroys the weather seals in the wiring harness.

EDIT: I have found that "car wash" codes disappear in an hour or two and don't come back. The ones that show the EBTCM going offline and even resetting its codes are new to me, first appearing about a year ago when I drove through a deep puddle (see first post in this thread). These, instead of going away, recur intermittently, and, in the past year, get more and more frequent and stay longer, until the car develops driveability problems; browse through the thread from the beginning to watch the progression of this, then the onset again a few months after I fixed it the first time by replacing the EBTCM - which included cleaning the connector. Apparently water comes and stays in the connector, or elsewhere.

Why don't I get a used harness? Two reasons - if it is there for the same reason mine would be, it wouldn't solve the problem, and, getting the main harness out of the car by myself would require that the engine be already out of the car and that I disassemble a significant portion of the interior of the car, and take a couple of days. For a daily driver that I would want for several more years, getting this harness new for $2K+ is my choice.

[Cadillac Jim]

News Flash! I was looking at the old EBTCM early this morning to try to divine the connector pinout when I realized that the connector latch mechanism was very apparent. I compared it to a photo I took of the connector in the car just before I put it in the shop. It is clear to me that the EBTCM connector was a few mm short of fully latched on the EBTCM.

Photo of the connector on the new EBTCM in the car:

Photo of the old EBTCM, showing the latch mechanism:

Look at the blue lettering burned into the connector, "T&B 16258747." The second photo clearly shows that there are to cogs at the level of the bottom of the "T" and a master latch at the bottom of the plastic connector. On the first photo, the connector doesn't quite reach the bottom of the "T" and the master latch is clearly a few mm short of snapping over the main latch.

Once the T-shaped connector latch is over the cog on the EBTCM connector, a locking pin can be inserted that keeps it from coming loose. If missing, a cotter key can be used, I suppose. In the first photo you can see that this locking key is clearly missing.

The EBTCM harness connector came unlatched and worked loose. That was the problem, at least this last time.

That doesn't solve the problem of the "car wash" codes but after a day at home, the car has been code-free across the board.

[KHE]

That is great news Jim! Glad to hear it's fixed.

[Cadillac Jim]

Once I showed these to my mechanic, we discussed the "car-wash codes" and he is getting in some silicone connector sealant and I am getting some large nylon wire ties. In the next week or two, he will pull the EBTCM connector and add the sealant to the connector O-ring, re-seat the connector, put in cotter keys in the connector locks (unless the Goodwrench tech already put in locking keys of some kind), and use criss-cross wire ties to provide a belt-and-suspenders additional hold-in for the EBTCM connector. Then he will go looking for dry connectors that are responsible for other "car-wash codes" and add sealant to their O-rings.

[Cadillac Jim]

Closure at last. I changed mechanics to get the EBTCM connector closed up and secured and all the EBTCM problems went away.

The miss didn't respond to the usual bad gas measures and was gradually getting worse, particularly in the mornings or when I got a fresh tank of gas. Due to the fact that I didn't have any history with my new mechanic and clearly didn't want to go back to the dealer (see post #29 on this thread), I got an engine analyzer and quickly identified coil no. 4 as the source of the miss. Changing the coils resulted in coil no. 4 arcing when we first started the car so we got wires and plugs. The plugs were OK but the wires were not OEM quality and appeared to be 1 mm short in width.

Now I'm back to no codes and a very strong running 1997 ETC.

[Texas Jim]

Closure at last. I changed mechanics to get the EBTCM connector closed up and secured and all the EBTCM problems went away.

The miss didn't respond to the usual bad gas measures and was gradually getting worse, particularly in the mornings or when I got a fresh tank of gas. Due to the fact that I didn't have any history with my new mechanic and clearly didn't want to go back to the dealer (see post #29 on this thread), I got an engine analyzer and quickly identified coil no. 4 as the source of the miss. Changing the coils resulted in coil no. 4 arcing when we first started the car so we got wires and plugs. The plugs were OK but the wires were not OEM quality and appeared to be 1 mm short in width.

Now I'm back to no codes and a very strong running 1997 ETC.

Glad to hear that you got the EBTCM problem and the miss fixed.

It is so nice to have one running well with no codes.

[BodybyFisher]

Nice Jim!

[Cadillac Jim]

UPDATE

Once the connector clamp was on and the locking pin replaced, everything was stable for a couple of weeks. but, the ABS and TCS lights started coming on again, and after a couple of weeks they stabilized into a routine. The lights would stay on most of the time, but would go off when I took off from a light, coming back on when the car's speed stabilized. They would stay on for some time, often until I stopped and took off again. The car would take off in 2nd gear and downshift to 1st when the lights went out. Sometimes the lights would go off with hard braking and come back on when I took my foot off the brake or stopped. In steady cruising, the lights would stay on for perhaps 10 minutes, then go out for about the same amount of time, then come back on. When the lights were on, the CURRENT codes were P1602, U1040, C1783, and C1785.

This is exactly the same problem I have had for over a year, except that when the connector was backed out and several pins would have intermittent or broken contacts. Until the bracket was installed, the lights would go on and off with bumps and potholes. The clamp held the connector firmly engaged, thus exposing the core problem.

At this point, I felt I had three alternatives:

• Take several days to rebuild the connector myself.
• Find a dealer that was willing to fix the car.
• Get another car.

The third alternative seems dumb but I list it here for completeness. With a chronic ABS/TCS problem the value of the car is zilch. And, I had not been able to get anyone to actually tear into the connector itself, in spite of the fact that I had identified all the problems as being with the connector. Mechanics on a flat rate do what they are told by their boss, and no one had been able to get the message that the connector itself needed to be taken apart (push the terminals through the connector and examine how the wires are attached to the spades, tighten them up and clean them, then pull them back into the connector shell).

So, I took a couple of days and thought the problem out from a clean sheet of paper. The first alternative, making a project of it, would require that I put everything else on hold for about a week because I would be busy and my car would be apart. That kind of down time isn't in my life plan. So, I went to http://www.cadillac.com, clicked "Locate a Dealer" and put in my ZIP code, then selected from the list a dealer that looked like it has a big service department. This was a big Chevrolet-Cadillac dealer in an auto mall. Remember, I bought my car from a Chevrolet-Cadillac dealer after going to make them an offer on a 1998 Corvette but could not get the Vette guys to show me an option sheet and sit down and talk turkey, while the Cadillac people found that I wanted their fastest car, located several on their lot, then started shoving money across the table until I bought my ETC. So, I called this new dealer and made an appointment.

The tech spent a couple of hours diagnosing the car. Thumbnail from invoice:

• No communications with EBTCM (see all the CURRENT codes above)
• Tested fuse(s) OK
• Found moving connector, that would power up the EBTCM

He found these specific problems:

• Bad ground circuit (he said G110 was a chassis ground but my FSM p. 8A-44-5 says it's an engine block ground - anyone have any hands-on experience with G110 or G107?). He said that the bolt was stripped and he used a new bolt.
• Pink wire was broken at the point where the connector spade was crimped onto the conductor. This wire goes to the 10 Amp BRAKE fuse.
• EBTCM connector was damaged, (tab broken off side)
• Several terminals were spread and making poor contact.

He installed new wiring and terminal for the pink wire, tightened up the loose terminals, repaired the connector (SuperGlue???), reassembled, reset all the codes, and test drove.

At this point the car has been code-free for a week. I check the codes every time I drive the car and there has not been a single set code displayed, not even HISTORY. The most sensitive codes to EBTCM glitches are C1783 and C1785, in which the RSS sees that there is no voltage on the EBTCM on the other side of the communications lines that pass road force data to the EBTCM to aid the ABS and Stabilitrak. Also, an IPC U1255 can be thrown if the EBTCM glitches. But, so far, nothing. Once again, I have a zero-codes car.

Based on my understanding of the problem and the description of the tech, who I also talked to at length after the repair, I don't expect any more problems. My confidence in the car is back, and I am thrilled every time I start it up again. And, the tech said he would be happy to see my car again, for *anything.* He had been there since 1988 and he had worked on 1997 ETC/STS cars when they were new. And, yes, he likes those cars, and he likes my car.

[WarrenJ]

Once again, I have a zero-codes car.

. . . And, the tech said he would be happy to see my car again, for *anything.* He had been there since 1988 . . .

Sounds like you hit pay dirt there Jim! Any condos for sale near him?