LS1B 8.1/4l85 with failed hypertech tune assistance

[Phil_Miller_86]

Background: I am in Nevada, USA (pacific time zone). I bought an 04 Avalanche 2500 with the 8.1 and the 4l85 trans. I *think* this is the LS1B ECM(?) The previous owner lifted it, slapped 35's on it and regeared to 4.56 front/rear. He used a Hypertech to adjust the shift points and account for the gear ratio/tire size.

I have a flash scan v2 I bought years ago when I had a previous truck tuned, so I grabbed some data logs. Then I realized, the Hypertech probably pulled bunk data so it would be best to de-tune with the hypertech before getting good logs for EFILive tuning.

I went to uninstall the hypertech tune and it failed to re-write the stock tune multiple times, giving code 8E and saying to call hypertech (they are closed weekends). The truck won't start now, and is parked on the street in front of my house. I don't really want to pay a tow truck to take it to the dealer if this is a simple procedure I can do with this device I have already paid for.

I pulled out my old computer, updated the EFILive software, the Flash Scan Firmware, bought a new VIN license and tried to read the tune that is on the truck. The result shows there is an invalid checksum in speedometer segment 8. I don't know where that is, or how to fix it. I exported the speedometer data into a CSZ file(?) but it looks like gibberish in notepad and I wouldn't know how to save it anyways.

Instead, I tried to modify some of the speedometer values that seemed waaaaay out of range (e.g. tire size = 11138.84"). I compared the data to some old tune info, and some files I found here, but the PCM wouldn't take my tune.

I've searched and read, and I feel like I'm fairly close to getting this resolved, especially if I can get a good stock file and change the VIN to match mine, or if I can read what this segment value is and modify it to something that works. I've read that there might be more in-depth solutions like updating the OS to the newer version and copying over my engine data, but this is really the first time I've done anything other than move tunes around from email to the truck.

Any assistance would be helpful, and I appreciate the time you took to read this post.

(I will have to post a few more times before I can upload files, I think)

[Phil_Miller_86]

[Phil_Miller_86]

This is the only file I have from the PCM and it contains an error.

LS1_0076 - 2004 Avalanche K2500 8.1 4L85E - Error in speedometer.ctz

[1FastBrick]

This is the only file I have from the PCM and it contains an error.

LS1_0076 - 2004 Avalanche K2500 8.1 4L85E - Error in speedometer.ctz

LS1B_2004 Avalanche 8.1L 4x4.ctz
This should be the latest OEM base file for you based on the Vin number from the file you provided. Hope this helps!

[Phil_Miller_86]

LS1B_2004 Avalanche 8.1L 4x4.ctz
This should be the latest OEM base file for you based on the Vin number from the file you provided. Hope this helps!

I thought I posted a reply to thank you, but I don't see it here. I appreciate your help, Thank you.

[joecar]

I'll look at your files when I get home from work (next Tuesday).

[Phil_Miller_86]

Update: I called Hypertech customer support about my experience and the code E8 that popped up on the tool. Dude said 'that code means the device needs to be replaced. we don't stock them or service them anymore, so you would have to have the dealership reflash it and buy a new device'.

My insurance covers the tow to the dealership and they are going to try to squeeze it in this week (there's a 3-4 week wait for service appointments).

I'd much rather just flash a new OS on it and call it good. I could even order a new PCM and install it before their appointment time opens up.

[In-Tech]

I have this in my archives, maybe it will help. I do NOT know the history of this file so adjust accordingly. 3GNGK26G84G291431 2004, 8.1l, 4l85E, 4X4.ctz

[Phil_Miller_86]

I have this in my archives, maybe it will help. I do NOT know the history of this file so adjust accordingly. 3GNGK26G84G291431 2004, 8.1l, 4l85E, 4X4.ctz

I appreciate your assistance here with a tune file. I don't know enough about this process to tell if the values look reasonable or safe for my vehicle but at this point I'm willing to try just about anything. I'm sure the dealership is going to want buku bucks to install a new PCM, and that's if they can source one.

I am currently trying to modify this file you sent to match my known information (I changed the VIN, the gear ratio, and the values in the speedometer settings to match my measured 33.5" tall tires). I noticed this file has a newer/higher number OS so I'm hoping that is a good thing and it will help me out.

I imagine I'm going to try a full-flash, any tips for me to prevent totally bricking the module?

[joecar]

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