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Help using PCM Hammer to program PCM for larger tires/gear ratio change

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1.5K views 16 replies 4 participants last post by  AstroWill  
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#1 ·
I have a 2000 Astro RWD, just went to 235/75/15's and 3.73 gear from a 3.42. Speedo is off 5 mph at 55 and I would like to correct it. After reading through a few threads here on that, I bought an OBDlink LX and downloaded PCM Hammer. Got the OBDLink LX and PCM Hammer talking to each other, but I am unable to get the PCM to unlock and be read by PCM Hammer.

Here's a quick snapshot of what PCM Hammer is telling me about the attempts to unlock it:

[04:56:04:370] PCM Hammer 021
[04:56:04:370] Friday, December 06 2024 @04:56:04:37
[04:56:05:461] Voltage: 12.0V
[04:56:05:508] Elm ID: ELM327 v1.4b
[04:56:05:524] ScanTool device ID: STN1155 v5.6.19
[04:56:16:133] Will save to C:\Users\cvn\Desktop\astropcm.bin
[04:56:26:242] Querying operating system of current PCM.
[04:56:26:398] OSID: 16265175
[04:56:26:570] The PCM didn't accept the unlock key value
[04:56:29:663] Unable to process unlock response.
[04:56:29:663] Unlock was not successful.

The full debug log:


04:56:04:370] PCM Hammer 021
[04:56:04:370] Friday, December 06 2024 @04:56:04:37
[04:56:04:370] ElmDevice initialization starting.
[04:56:04:555] TX:
[04:56:04:571] TX: AT Z
[04:56:05:414] ELM327 v1.4b
[04:56:05:414] TX: AT E0
[04:56:05:446] AT E0 OK
[04:56:05:446] TX: AT S0
[04:56:05:446] OK
[04:56:05:446] TX: AT RV
[04:56:05:461] Voltage: 12.0V
[04:56:05:461] TX: AT I
[04:56:05:508] Elm ID: ELM327 v1.4b
[04:56:05:508] Initializing PcmHacking.AllProDeviceImplementation
[04:56:05:508] TX: AT #1
[04:56:05:524] This is not an AllPro device.
[04:56:05:524] Determining whether PcmHacking.ScanToolDeviceImplementation is connected.
[04:56:05:524] TX: ST I
[04:56:05:524] ScanTool device ID: STN1155 v5.6.19
[04:56:05:524] TX: STPTO 3000
[04:56:05:539] OK
[04:56:05:539] TX: AT AL
[04:56:05:539] OK
[04:56:05:539] TX: AT SP2
[04:56:05:539] OK
[04:56:05:555] TX: AT DP
[04:56:05:555] SAE J1850 VPW
[04:56:05:555] TX: AT AR
[04:56:05:555] OK
[04:56:05:555] TX: AT AT0
[04:56:05:570] OK
[04:56:05:570] TX: AT SR F0
[04:56:05:570] OK
[04:56:05:570] TX: AT H1
[04:56:05:602] OK
[04:56:05:602] TX: AT ST 20
[04:56:05:617] OK
[04:56:16:133] Will save to C:\Users\cvn\Desktop\astropcm.bin
[04:56:26:242] Querying operating system of current PCM.
[04:56:26:242] TX: STPX H:6C10F0, R:1, D:3C0A
[04:56:26:398] RX: 6C F0 10 7C 0A 00 F8 2F D7
[04:56:26:398] OSID: 16265175
[04:56:26:398] Suppressing VPW chatter.
[04:56:26:398] TX: STPX H:6CFEF0, R:1, D:2800
[04:56:26:445] RX: 6C F0 40 68 00
[04:56:26:445] Sending 'test device present' notification.
[04:56:26:445] Setting timeout for Minimum, 0 ms.
[04:56:26:445] TX: STPTO 0
[04:56:26:461] OK
[04:56:26:461] TX: STPX H:8CFEF0, R:0, D:3F
[04:56:26:477] Empty response to STPX with data. OK.
[04:56:26:477] Setting timeout for ReadProperty, 25 ms.
[04:56:26:477] TX: STPTO 25
[04:56:26:477] OK
[04:56:26:477] Ignoring chatter: 6C F0 40 68 00
[04:56:26:477] Sending seed request.
[04:56:26:477] TX: STPX H:6C10F0, R:1, D:2701
[04:56:26:523] RX: 6C F0 10 67 01 5E 5E
[04:56:26:523] Parsing seed value.
[04:56:26:523] Sending unlock request (5E5E, 34EF)
[04:56:26:523] TX: STPX H:6C10F0, R:1, D:270234EF
[04:56:26:570] RX: 6C F0 10 67 02 35
[04:56:26:570] The PCM didn't accept the unlock key value
[04:56:27:601] Timeout during receive.
[04:56:27:601] No response to unlock request. Attempt #2
[04:56:28:632] Timeout during receive.
[04:56:28:632] No response to unlock request. Attempt #3
[04:56:29:663] Timeout during receive.
[04:56:29:663] No response to unlock request. Attempt #4
[04:56:29:663] Unable to process unlock response.
[04:56:29:663] Unlock was not successful.

Yes, my voltage is low. That's a brand new battery I bought today too, it's just cold as shit outside right now. I'll try again tomorrow with the charger hooked up to it, I know low voltage can cause issues during write and reflashing and such. But I don't have high hopes for it being related to low voltage, seems more like another issue. Just my luck, my PCM is probably too old or just not compatible. I registered over at the pcmhacking forum, but my account has not been approved so I can't post there yet. Figured I'd ask here and see if you guys have any ideas why the PCM is not able to be read by PCM Hammer.

If I can't get this working in the next day or two I will be ready to throw in the towel and just pay someone to program it, if that's even an option. I am running out of time with my project, completely swamped with a million other things that need to get done and just don't have time to figure out this tech stuff. Don't live in a big city so there's noone local that could do that kind of thing. Suggestions on some place I can send the PCM away to have this programming done, if I can't get it working this weekend?
 
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#2 ·
I don't have any helpful hints on pcm hammer, I looked at it before, it went over my head, and I have other things I'd like to focus on learning, but if your thinking about paying someone to change the tire size in your computer you can buy a fairly inexpensive bi directional scan tool that will do it, plus have the added benefit of being able to use the tool for other uses on your van. The one I bought is now only around 150 canadian dollars and it updated tire sizes no problem, used it test my injectors, test my idle air control valve, read codes, live data etc

The price to pay someone else may get you a useful tool
 
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#3 ·
I don't mind buying a tool if it works right out of the box and doesn't require technical set up and such like PCM Hammer. What was the name of the scan tool you bought? Before I found PCM Hammer, I was looking at the hypertech programmer, but it's really expensive and seems like it has a lot of issues. Also, it sounded like it could only be used on one vehicle, meaning I can't use it and then resell it.
 
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#4 · (Edited)
Also, I googled my OSID (16265175 ) and didn't get any matches, so even if PCM Hammer did unlock the PCM, I still need to find the XDF file to match the OSID (I think that's what I need to do anyways), so it doesn't sound like PCM Hammer is going to work for me. Bummer. Too bad I had to buy the OBDLink tool to find this out, no way of knowing that OSID beforehand.
 
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#5 ·
I believe this is the one I bought, https://www.aliexpress.com/item/100...BhAcEiwAQH28Io3g6j_XSuMJnSTrOx1xMNC84CmhX51neetbaq8Tz5EP2SpiHorE7RoCAywQAvD_BwE

I bought mine off amazon earlier this year, but when I googled this was the first one I found, make sure where ever you get one it is loaded with the gm software, like the one linked above you can select it for other brands then it wouldn't have the gm stuff loaded on it, I am sure there are other brands that are just as good or better but this one is working for me. Do some googling and a youtube search for bi directional scan tools 2024 and should kind of help learn what there all about now a days
 
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#6 ·
I don't have an account there so the link won't pull up the listing. Do you have an amazon link, by chance? Thanks for the tip on the "bi directional scan tools 2024" keyword search, that got me going in the right direction. None of these tools were showing up for me with the search terms I was using. I'll be looking into it more later this evening.
 
#7 ·
Another option for you as you already have the hardware and want to use the free tunerpro and pcmhammer is to change your PCM and software to a supported one.
 
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#8 ·
I was unaware that I could use a PCM other than the one that came in my van from the factory, from the same year with those specific options etc. Could you explain how that process works? I'm pretty clueless when it comes to all this PCM stuff.
 
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#9 ·
I am not seeing the one I bought on amazon for gmc anymore, they have the one for handa and toyota but not the one with gmc software, the model I have is Launch creader elite x431
 
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#10 ·
Is this the one you bought? Amazon.com

Also found the same model on ebay for HALF price... It only has GM loaded, whereas the Amazon one had multiple brands. I only need it for GM so half price is fine with me! https://www.ebay.com/itm/405044964816?_skw=LAUNCH+X431+Creader+Elite+2.0+gm&itmmeta=01JEKH08Q7BB0W3783WYQMJMWM&hash=item5e4e8fadd0:g:iJwAAOSwH7hnIZU~&itmprp=enc%3AAQAJAAABAHoV3kP08IDx%2BKZ9MfhVJKnoo9R8icAvE62F%2FcQ7ms51wC7ZTUMWFOFqytZweYSOuj316bL0317ysVPHH7%2BEmOqBj2fI1P1KxgTlOypExrRUkXqECkfCxa%2BW6JDrePROLzD%2BWplyIQsKtGUv3yBYId5XXiZsru4fWZKw8cOcme0uLfR15LG8QFq8Vv%2F6upaq0ups%2FbwYceTsEztlwMNguN90uyG559JYQAbjWHFaNOWtDPmHZlyi9dsztK4271A39UpY2VSqF2IgKiffDYFSEqF8WHbTcvGnvvHboZ0QuAhi37yoKKVhOWiKpRz6q%2FvlQEBxpn5gybV5eZf33g%2F8X90%3D%7Ctkp%3ABk9SR9qLgfH0ZA

It says it supports GM and it says there is nothing else to buy in "the mall", sounds like it's loaded with all the necessary software. I don't see anything in the listing mentioning the ability to change tire size or gear ratio though, nor did those terms show up in the reviews. But if this one worked for you, I think I'll give it a shot.
 
#11 ·
SeekingAstro said:
I was unaware that I could use a PCM other than the one that came in my van from the factory, from the same year with those specific options etc. Could you explain how that process works? I'm pretty clueless when it comes to all this PCM stuff.
Click to expand...
If all you want to go is change your rear end ratio and the tires, it's probably not worth it.

Basically you have to match up the old pcm wiring to the new pcm by removing the pins from the old connector and putting them in the proper places on the new connector. Then you have to flash a supported OS and tune to the new pcm.
 
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#12 ·
The amazon linked one you showed me is I believe the newer version of what I bought, mine the screen is vertical not horizontal, but I think it should probably do all the stuff, I'm not an expert I didn't even know mine would do tire size until I started playing around with it.

Here's a review on both styles of that scanner


 
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#13 ·
AstroWill said:
If all you want to go is change your rear end ratio and the tires, it's probably not worth it.

Basically you have to match up the old pcm wiring to the new pcm by removing the pins from the old connector and putting them in the proper places on the new connector. Then you have to flash a supported OS and tune to the new pcm.
Click to expand...
Ah, that's definitely more than I want to get into at the moment. It sure would be cool though to be able to use PCM Hammer though.

van again said:
The amazon linked one you showed me is I believe the newer version of what I bought, mine the screen is vertical not horizontal, but I think it should probably do all the stuff, I'm not an expert I didn't even know mine would do tire size until I started playing around with it.
Click to expand...
I found a video that showed the tire size function in detail. Pretty cool. Have you seen gear ratio in there? I've sent a question to the amazon seller asking them too. I can't find any references to gear ratio being supported on the Launch. If not I might be stuck with the hypertech. So far it's the only tool I've come across that specifically states it can change both tire size and gear ratio.
 
#17 ·
Wow, no way I'm spending $230 just to change tire sizes. I can do it for you cheaper if you have the time to wait for shipping back and forth. Send me a PM.

The full version of the x431 looks pretty darn good, until I saw the update fee of 199yr.
 
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