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TCM and Internal Harness fail.

btfarm

btfarm

America First!
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Sandwich, Illinois
Out of the blue I had my trans fail big time today. Shifting from neutral to drive and it slammed into gear and sent a message about stability control and park assist faults and was limited to 3rd gear on the way home from town. I read 46 transmission codes set. Called around but the only Allison service available was the GM Dealer in town. Couple of others said they could look at it sometime in mid June. Diagnosis is a bad TCM and internal harness. Both apparently common problems. Nobody has stock nearby. The search will go nationwide tomorrow. About 1600 bucks and 3-5 days is the estimate. SHIT! Rental car lined up for tomorrow. Told the wife I wish I'd kept the 06 LBZ. It turned 394k 2 days ago still on all original powertrain and fuel system.
 
those newer systems run off from Can Bus, each wire in the harness is actually a communication line rather than power and grounds. any change in radio interference can cause ill effects. most of the critical ones in the harness are wrapped in twisted pairs and shielded, but the shielding will ware through since it's just a foil wrap. the slightest loose connection at any of the connectors or change in resistance (like ageing sensors beginning to fail) can wreck havoc on can bus systems making almost impossible to diagnose. that's why most shops including the dealers will just replace both the ecm and harness, then when the problem persists, they go after the sensors "if" they are serviceable. if not, then it's the whole tranny or 4x4 unit!!!
 
My daughters 06 Jetta is can bus. we chased random light bulbs going off and on for about 6 months until I discovered that we HAD to use VW oem bulbs in it. we couldn't just install the standard 1156 turn signal bulbs or 194 marker bulbs. the internal resistance on those bulbs was slightly different and the ecm was randomly detecting shorts and faulty bulbs. it would somehow shut off the one bulb and keep others that were in the same circuit path going even though they were connected together!!!!

I attempted to install an aftermarket stereo with a screen and backup camera it her car... that didn't go so well. the backup camera had to probe a pos wire into the reverse lights. well when I did that it sent the rear lights into a frenzy, plus that car has no true switched ignition power. all controlled by the can bus and the ecm. you have to buy some sort of brain box that connects to where the radio did and it talks to the ecm, converts can bus to normal hots and grounds and gives you a switched hot for aftermarket radios. finding one that speaks VW German language isn't cheap!!
 
MrMarty51 said:
Shingles shot. I have been told by several people to het that and I keep forgetting.
If the clinic is open tomorrow, I hope I can remember to get the shot.
Thank You for mentioning that.
I hope that Your shingles dont last long and are not too painful.
Click to expand...
I highly recommend you do that. I'm taking the 1 week of horse pills in the hindsight version. This is excruciatingly painful. Kind of like getting repeatedly stabbed with an ice pick in random areas without warning. Fortunately, it's not as bad laying down so I can sleep ok.
 
The shielded wire is both a learning curve the automotive industry is going through, and penny pinching making it worse.

In the rest of the electrical world learned the hard way so ALWAYS have an insulation jacket over the shielding to protect it. But that extra layer of insulation raises the price of the wire. How much is used in each vehicle would raise the cost by MAYBE a dollar per vehicle. So as the owner who diy repairs, we wish they would do it. But the manufacturer makes 20 million cars with it, so that becomes $20 million in profit or loss. And when it fails it is almost always out of warranty. So that means to the manufacturer you should eliminate that rig and buy a new one.

As the dealerships have more problems of the mechanic damaging it and the dealership eating the cost of replacing the harness, they will apply leverage and make the manufacturer add the insulation over the shielding. This will happen as more and kore of the rig gets low voltage control and information sending while fighting the high voltage electrical cabling.

The communications industry learned it and applied it within 5 years. The rest of the electrical industry took 10 years more. The auto industry will just redesign their individual harnesses based on last models weak points. So I would bet it is not until the rig is all electric that they use proper insulation over shielding cable.
 
TCMs and internal wiring are both common problems on these trucks. Alot of times when I get a code list that long its turns out to be a bad TCM. The internal harness usually is only replaced if its leaking through the connector which is also very common.

CAN systems are not that hard to diagnose if you know what your doing. I've gotten in the habit of using a lab scope to watch the communication data. That way I can physically see what's going on.
 
MrMarty51 said:
Shingles shot. I have been told by several people to het that and I keep forgetting.
If the clinic is open tomorrow, I hope I can remember to get the shot.
Thank You for mentioning that.
I hope that Your shingles dont last long and are not too painful.
Click to expand...
I have been after my wife to get the shots.
I take Acyclovir. The shot is supposed to be over 90% effective.

Acyclovir is supposed to be over 98% effective.

I think Acyclovir may also be helpful in treatment. Not positive on that and hope I never need to know.
 
I’ll have to check out that stuff.
I do have a doc appt on the 10th or so. Probably wait and gettit done then.
Wifey thinks I can get it done at the pharmacy but I think the doc for Me.
Have another appt with the same doc for a physical before the back doc will do the fusion. If a second dose is required, can gettit done then.
 
MrMarty51 said:
I’ll have to check out that stuff.
I do have a doc appt on the 10th or so. Probably wait and gettit done then.
Wifey thinks I can get it done at the pharmacy but I think the doc for Me.
Have another appt with the same doc for a physical before the back doc will do the fusion. If a second dose is required, can gettit done then.
Click to expand...
Drs. Office told us to go to the pharmacy for the shingrix shots
 
I had a case of shingles a while back. It was on my face and head. Followed a nerve. Very painful and annoying. Hope you feel better soon Mike.
Hope you get your truck running soon too.
I'm thinking of taking a step backwards and buying a 1999 Dodge 24v Cummins with a 5 speed manual.
 
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