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Discussion Starter #1
Hi everyone, I've been away for quite a while. Changed jobs, was still commuting, car has been trouble free 150K miles.

Until yesterday.

Turn the wheel sharp as I hit the brakes to pull into a business, and the ABS cycled. Finished my turn, found a parking spot instantly and turned off the key. When I came out of the business, I noticed the telltale trio of DIC warnings.

Stabiltrak, Service Brake and ABS.

My 2 code readers do not read ABS, so I just ordered a BlueDriver Bluetooth for my Iphone 6.

I also ordered (2) Dorman 970-040 harnesses, uninsulated butt connectors and a variety pack of adhesive shrink tubes. I plan on checking to see which side is causing the issue, but I know I'll do both sides if not now, eventually.

I plan on soldering the butt splice connectors after crimping.

I was laid off for 11 weeks due to Covid, got called back and asked to work overtime each week, but my job and another guy's job eliminated after 2 weeks. So no insurance during a pandemic, with jobs scarce, and I'm pushing 60. And when I start work, I have to wait 90 days for insurance, so COBRA here I come. :(
 

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On my 2012 I've still had a hell of a time locating the exact issue.

My car doesnt get the abs warnings but does get stabilitrak/traction control/door locks cycle when they shouldn't...and the other day mileage display went blank...oohh and the shitty limp mode(3rd gear only) top speed of 50mph.

When this stuff happens on mine only code I get is the lost communication with tcm...forget the u# that shows up.

Narrowed it down to where wire harness plugs into transmission. Mine happens when I hit a rough bump. Not so much from turning.

Hopefully yours is just the abs harness at either wheel.

Good luck
 

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Discussion Starter #3 (Edited)
On my 2012 I've still had a hell of a time locating the exact issue.

My car doesnt get the abs warnings but does get stabilitrak/traction control/door locks cycle when they shouldn't...and the other day mileage display went blank...oohh and the shitty limp mode(3rd gear only) top speed of 50mph.

When this stuff happens on mine only code I get is the lost communication with tcm...forget the u# that shows up.

Narrowed it down to where wire harness plugs into transmission. Mine happens when I hit a rough bump. Not so much from turning.

Hopefully yours is just the abs harness at either wheel.

Good luck


Normally, when things like this come up, they say to check the grounds first.

I'd also suggest you could have multiple intermittent issues.

As in an intermittent ABS harness wire issue, and a separate wire issue effecting the engine.

I don't have any specific experience with this but I've seen a few posts about the harness that wraps around the trans, looking down from top, at the right rear (drivers side) rubbing the trans case corner and causing varied intermittent issues.
 

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Discussion Starter #5
Plugged in the BlueDriver when it arrived today and I got 2 codes. First was lost radio comm., and second was the dreaded C0035, which is exactly what I thought I'd see. For all I know, the radio code could have come about doing the Rosen install a coupe years ago. The onslaught of codes came during a quick sharp left turn; and I had the feeling it was going to be the LF. Having the BlueDriver is sure nice to be able to find which ABS signal I was missing, AND being able to reset the code without pulling a battery cable and losing all my presets.

But as for the ABS code, I cleared it and it didn't come back, although I expect it to.


I got the harnesses, and the 14-16 AWG uninsulated butt connectors today, and I ordered the 16-22 AWG size too, since I wasn't sure which wire size the harness is.

I'm going to drive it and see when the trouble code comes back, since I have to wait another day for the smaller size connectors to arrive.

Really impressed with the BlueDriver; I wish I would have just done this buy before I I bought the cheaper engine only readers I bought. :confused:
 

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Discussion Starter #6
I was hoping to get this done right away, but now Amazon says it's coming Sunday, it was due today.

Glad I didn't start into the job of cutting out the old one. :(
 

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I'll have time to look at mine friday morning. Glad you commented about other areas of harness..a little searching and I found that tsb.
 

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Discussion Starter #8 (Edited)
I finally got to replacing the drivers side harness today. I had cleared the code and although I hadn't driven a lot, it did not return, but it's too common to not be an early sign of trouble, so I got under it and checked out the harness.

First, after unplugging it, a whole lot of water came out of the conduit. I'm talking about a spot of water about 12x14, on an unsealed driveway. Then I noticed that the conduit was installed so the split was perfectly "up" along the whole length of conduit, all the way back to the trans case conduit anchor. It was a literal eavestrough, but with no way to drain.

I suspect that in some cases, that water being trapped in the conduit could splash towards the connector and short the two pins together. I don't know that that's what happened in my case, but it sure could be problem for someone, especially if they are all built that way, OEM. I considered "nipping" the conduit on the passenger side if I found the conduit slit on the top. I noticed that the Dorman replacement was built with the slit "Down' the entire length of the harness, and I made sure to maintain it that way during the install.

I unplugged the connector and stripped back the conduit to the shrink tube like sheath that surrounds the wires. There was a noticeable flat spot in the sheath, which seemed like the point that the conduit, sheath and wires "kinked". This is the spot where every thread and vid on youtube on this subject find an intermittent break in one or both of the wires.
 

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Discussion Starter #9 (Edited)
So, I got out all the tools and gear, and went to it.

I wanted to make the splice out of the wheel well, being this is a wintry state, but I did not like the prospect of doing all the work I need to do reaching down around the trans harness, after pulling the air box to even get there, so I spliced in where everybody else does, near the front of the A arm, as the harness disappears out of the wheel well and hugs the trans case.

I used uninsulated tinned copper butt splice connectors, These.

I actually remembered to put the shrink tube on before I crimped the butt connectors on, These.

I soldered the wire into the connectors after I crimped them in with a butane powered solder gun I bought on Ebay about a year ago. I love this thing, but they don't make them like this anymore. It's a refillable, self-igniting butane powered soldering iron. "Ultratorch", Master Appliance UT-40Sik. I got turned onto these at work, and after one use, I wanted my own. So I searched and waited for one to come up on Ebay. It's light, small, like a screwdriver, you click the On switch, it lights, it warms up real fast, and you click it off with a different button. It's a joy to use, when I can't sit down at a bench or table with my Weller WESD51.

I kept all the twist in the 2 wires I could to act as a field resistance, and after heat shrinking the tubes on with an extended lighter I light the grill with and sealing the ends of the shrink tube with liquid electric tape, I twisted the wires a bit more and then wrapped them with 3M Scotch Super 33+ electrical tape. I got turned onto that stuff when I was doing highway and airport runway electrical work. I sectioned the new conduit to the old and taped them together.

The worst part of the job, and I do mean it was bad, was putting the conduit anchors into the punched holes of the A arm. I spent about an hour trying to get these to go into the holes. The old ones popped right out with a steel handled trim removal tool, a sort of V'd pry type tool with a screwdriver handle. But getting the new ones to seat into the holes took trimming the "scales" of the anchors little by little to try to get them to install without taking too much of the material away that they would fall back out of the holes if tugged on. Even after trimming them on all sides, making them a V shape to enter the hole as a small diameter, but a larger diameter farther up, I had to take the conduit out of the anchor and push using the side of screwdriver to get them to seat, then put the conduit back into the anchors. I tried to not do that so I would changed the position of the conduit to the anchor points, so I did it one at a time to preserve the spacing along the length of the conduit, to ensure I still had the more generous length at the "bend" where they connect to the speed sensors.

It's like any home improvement project, by the time you're done, you're an expert, but son of a -----. 🙁

I put it all back like it needed to be, put on the wheel and actually torqued it, and dropped it off jack stands, confidant it'd be right and it was.

No codes on the way to Costco this afternoon.
 

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Discussion Starter #10
Aww geez,

Took a trip down the highway yesterday to visit a seafood company, and coming home, after getting off the highway and back to 2 lane, I jumped on it doing a left from a stop sign and the trio of codes came back.

I've seen people do the hub assembly and not fix the problem so they do the harness and it does.

I did the harness, since it is so common, and it showed the same issues as I've seen in posts and vids.

This is a 2016 Limited LTZ, 153K miles IIRC: conduit was full of water and the wires showed a sharp kink at the bottom of the short travel loop near the sensor connector.

I have another hub assembly, but before I swap it in, I'm a little skeptical of how this playing out.

I do not believe this is an issue with the recently replaced harness, as it was fine until I nailed it hard while turning relatively sharply left, just like the first time I set codes with the OE harness.

I don't think the current hub is loose, and after a tire rotate and balance I had it aligned, since I had some slight pull and I'd only done it once before, last year. The alignment guy never mentioned it, nor the tire guy, and I tried throwing it around a month before all that when I did rotors and pads, and it didn't seem loose.

Is there something else besides the harness and the hub asembly/speed sensor that I should check?

I'm starting to think I've got gremlins in the ABS and Rosen. 🙁
 

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Try looking at the tcm connector like in my post.

I to had thought I fixed mine about 15k ago by replacing front left wheel harness

I think it was the wiggling and jiggling of the main harness it branches from that temporally fixed mine.
 

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Discussion Starter #12 (Edited)
Try looking at the tcm connector like in my post.

I to had thought I fixed mine about 15k ago by replacing front left wheel harness

I think it was the wiggling and jiggling of the main harness it branches from that temporally fixed mine.
I sure don't want to do all the stuff they say to do in the TSB, I want to inspect the harness(es), look for abrasion, put something around the conduit to offer more protection, and see if I can get by without having to remove all the things they say to remove, cut open main engine harness(es), and then have to put it all back. That's asking for other things to have issues.

If there is minimal damage, perhaps a wear thru point in the conduit and a nick in a wire insulation that contacts only intermittently, I'm not lazy, but I'd like to do the minimum I need to make the issue go away, without risking more damage to all the other items they say to remove and remount.

What exactly did you do to fix this issue?

Did you just rearrange the conduit as it lay across the trans corners?


I'm thinking of finding something like a tennis ball or something like that, cutting a piece of it and taping it underneath the conduit, and seeing if the issue is "mitigated". At 154K, I don't foresee keeping this around for many more years.

I'm a big believer in "mitigation". ;)

I saw a vid on youtube of a guy who was pretty OCD, and he was replacing the Drivers Side ABS harness on his Impala for the 3rd time for the same trio of issues.

I am starting to think this happens a lot more often to people than just the ABS harness issue, which is a legit issue, but the number of circuits involved in that TSB, which includes several of the ABS, leads me to believe this is a pretty common issue that manifests itself in a myriad of faults, and therefore effects many vehicles.


Now, what's like a tennis ball that I already have laying around here... ?
 

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If the problem is at the tcm end...its not that big of a deal.

Disco battery.
Remove air box/ecm
Disco water line from engine block
Disco tcm connector

Can be done without other steps. Definitely would be easier pulling entire harness up to top of engine bay.
 
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