I just shorted my TCM

  • Thread starter Deleted member 32467
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Deleted member 32467

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3 months and thousands of dollars later...

I fired my truck for the first time last night with borrowed batteries as my new ones had been ordered. While re-routing cables tonight, the new passenger side battery was connected and I think I drug a drivers cable across the TCM. I remember seeing a small spark.

Sure as shit, no crank anymore. If I lean the TCM against the negative post it starts but dies after a second, dash says something about reduced power. I have no continuity between pins 9 and 69.

Is the dying after it starts normal? I see threads where guys solder a lug from the TCM case heat sink and the battery negative terminal or body ground and go on there way.

Where do I get a TCM like 911? Overnighted, drive across the state (Utah) tomorrow, whatever. Does the new TCM have to be programmed for my VIN somehow?

Supposed to drive across the state pulling all my families toys next week. I am not even mad, just super disappointed in myself, and GM for putting that metal heatsink case right by the battery.

Thanks for any help.

I have cross posted on forums, but I am desperate for quick answers. Thanks fellas.
 
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Deleted member 32467

Guest
Whoops,

LBZ 06.

Reading online I need an A40 which has been updated to an A46?

A GM 24256864 seems to be the A46 number.
 
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Deleted member 32467

Guest
When I ground the case it start, runs for 1 second, and then dies?
 
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Deleted member 32467

Guest
I just swapped TCM's from my other truck, it starts and runs for 1 second and dies, headed back out to try a VATS relearn
 
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DAVe3283

DAVe3283

Heavy & Slow
Sep 3, 2009
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Boise, ID, USA
When the truck dies, does the security light on the dash come on? It might have lost the VATS (antitheft) key when the batteries were disconnected.

If that is the case, you just have to do the VATS relearn, which doesn't take any tools, just 30 minutes of your time.

If you swap ECUs, you will almost certainly have to do the VATS relearn as well.

I don't know why GM removed the plastic shield over the TCM. Older trucks like my LB7 have a plastic shield so you can't accidentally short the battery cable to the TCM.
 
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Deleted member 32467

Guest
Confused...

Went out to do the VATS procedure and on the first cycle it started right up and stayed running. It had 14 codes, cleared them and it smoothed out and I brought it up to operating temp and all seems well, it restarted again after.

Better get this on the road ASAP to make sure I do not have a gremlin somewhere, I was pretty concerned I had shorted out the ECM as well.

Thanks for the replies, I will report back!!
 
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