When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Has anyone ever had their ECU bricked? My '96 was tuned by the PO. But before I drop coin on rebuilding a tranny. I want to make sure that the "tune" didn't jack up my shift points on my 4L60e. Because if the ECU has bad shift points, the new tranny is still going to give me problems (In Theroy) So I'm taking it to GM to re-flash the shift points. The manager there is afraid of bricking the ECU, and explained the risks to me. But I figured I'd just buy a new ECU if that were to happen.
I don't know anything about this. I am just amazed your local Chevy dealership can and will reflash shift points. My local dealer would look at me like I had two heads. Dan
I don't know anything about this. I am just amazed your local Chevy dealership can and will reflash shift points. My local dealer would look at me like I had two heads. Dan
I asked my Dealer to check the resistance on my ignition key. I got the 2 heads look on that simple one. I left knowing we are truly all alone out here in the wild....
How did the PO tune it? Was it a mail order tune, like from PCMforless, or did he just flash it with an old Hypertech unit?
You are on the right track. You will want that ECU stock before you do anything related to the transmission.
From I understand, he took it in to some shop that's three hours away, and they deleted the egr and air injection, followed by a tune. A few weeks later, a code popped up. And he tried to clear it with s scanner of some sort, and that's when it stopped shifting (supposedly). I talked to the tuner about it, and he believes that the PO corrupted the TCM.So he wants $150 to fix the issue. The GM manager thinks it was tuned specifically for the strip only. Like many, I don't know anything about the "tuning/deleting" process.
What is the car year ? If it’s a tunable PCM the shift points are easily adjustable . I missed the “Bricked “ part . Is it bricked ?
GOD bless ,
Robert
This has been discussed many times before. If the ECM was "bricked" the car wouldn't run. Yes the shift points can be changed.
For the layman (or shops) to tune a '96, they would need a Jet DST unit (before the original software was sold to Jet, or for businesses) the software that became Jet DST is/was available.
BUT it still takes specialized software/interface to deal with the 1996's.
Update: I took it to GM, they asked again if I wanted to move forward. And I agreed. They then hooked up the computer to the car, reviewed everything, reflashed the transmission controls and..... well nothing. Of course not entirely, I learned that the the shifting wasn't really happening as I thought it would. On the ECU side, everything is fine. But for some reason, the tranny isn't responding to the computers commands. Even when I tried forcing it to shift using the diagnostic computer itself (yes, I got to play with the computer). It still does nothing. While the computer is already at four, it's still in first physically. The gear selection cable/switch is working fine too. Now that I know 100% that it's mechanical and not a bad tune. I can move forward in comfort. It was cool as hell looking at all the entire values of each component on the computer. Seeing it all in action made me feel like a kid again.
I asked my Dealer to check the resistance on my ignition key. I got the 2 heads look on that simple one. I left knowing we are truly all alone out here in the wild....
Most hardware stores, Lowe's, home depot, Menards can make a vats key. You just need a key for them to copy. Gm only used so many different resistance slugs. It's best to keep the original key in a safe place then you will always have it to get copies made. Cost me 15 bucks for 3 sets of keys for my 91 at local ace hardware store.
Id eliminate that vats stuff, pass.
id think the next step is to have your trans diagnosed, somebody was in the tool box that had no biz being in there.
Youll get it sorted, at least you ruled out one thing.
Id eliminate that vats stuff, pass.
id think the next step is to have your trans diagnosed, somebody was in the tool box that had no biz being in there.
Youll get it sorted, at least you ruled out one thing.
I agree brother. After watching a grueling two hour video on the hydraulics and electrical of a 4L60e. My next plan of attack is the Automatic Transmission Fluid Pressure switch (TPF). Reason being that's where the transmission fails to communicate with the ECM/PCM. Both manually, and while on OD. Any thoughts???
While connected to the computer, the ECM would shift through all the gears on OD, and shift through the gears manually, showing what gear it was on the whole time. But the tranny wasn't physically shifting. For example: You would shift to second, the computer saw second, sent the command to shift to second, and you can feel where it wants to shift into second, but it doesn't shift to second. Even when you tried using the computer to override the ECM's commands to shift. It's as if the valve was opening up just a little. As for codes, there was none present. The tranny shifts into first and reverse just fine, in fact you wouldn't think there was a problem.
I'll ask again. If you're driving this thing around to GM dealers for diagnosis, I suspect it is not in 1st, but is indeed in 3rd.
Have you checked fuse 17?
I’ve gone through every fuse. Even the ones by the battery. Also, my gm dealer is three blocks away, not city blocks either lol. The rpm’s are over 2.5k-3.5k, and I’m only going about 10-20mph. I figured at third I would be going faster. Which takes me back when I had a pump go out on my ‘90 L98. I only lost OD. I was still able to drive it on the highway, I have to take the back roads with this one. We drove around running diagnostics and real time data streaming… and the rest is history
Without power from the fuse, or if the large connector on the transmission is disconnected, the transmission vill be in "limp mode". ( No 12V supply to the solenoids.)
From what I read:
* You should get second gear if the stick is in 1 or 2.
* You should get third gear if the stick is in 3 or D.
* You should also have no TCC lock.
Without power from the fuse, or if the large connector on the transmission is disconnected, the transmission vill be in "limp mode". ( No 12V supply to the solenoids.)
From what I read:
* You should get second gear if the stick is in 1 or 2.
* You should get third gear if the stick is in 3 or D.
* You should also have no TCC lock.
All the solenoids click when we over-rided the ecm, and sent the commands via computer. So they’re getting power. You can also have the selector lever on 2, D, OD, and it will still stay on first, no matter what. All connections are good. Power going through it all. But no shifting. But I did however, drive around the block without the fuse. And it did the same thing, but this time with three codes (P0753, P1860, and P1864. When I got home, I cleared the codes, and went around the block to no avail. But at least we tried, right?!
Last edited by TheKodiak; Jun 1, 2022 at 02:52 PM.
Bricked ECU
