Cant read ECM

New here to HP Tuners and I was trying to read my ecm on my 02 4.3 V6 Blazer to play around with the software. I know at my ecm was replaced by a shop do to the factory one going out. When I try reading it with HP I get a "Request Download x7F Negative Response Code", from what I read around here is that the ecm my be locked. Im almost positive its never been tuned before but not sure if the shop had a handheld programmer on it to get it to work with my truck. Is that a way I can work around this?
Attachment 57835

OK figured it out. Just needed to be power cycle the truck.

For reference what exactly do you mean by power cycle the truck?

I am having the same issue. I have no problem at all reading and tuning several Gen3 and Gen4 GMs over the last few weeks but I cannot connect to my friend's 97 4.3 S10 Blazer. I also get the message, "Request Download x7F Negative Response Code" if I try to read it under Vortec, GM. If I try to read it under V6_97,GM V6 I get the message, "Controller Unlocker: x35 Invalid Key". Again, all I have tried to do so far on this S10 is read it. Any help? Please?

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Originally Posted by IARLLC

I am having the same issue. I have no problem at all reading and tuning several Gen3 and Gen4 GMs over the last few weeks but I cannot connect to my friend's 97 4.3 S10 Blazer. I also get the message, "Request Download x7F Negative Response Code" if I try to read it under Vortec, GM. If I try to read it under V6_97,GM V6 I get the message, "Controller Unlocker: x35 Invalid Key". Again, all I have tried to do so far on this S10 is read it. Any help? Please?

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it is NOT the same issue.

97 4.3 S10 blazer is not a supported vehicle.

Ouch! Thanks for letting me know Bill. Can you suggest an option for me on this?

It is actually a swap (97 CPI 4.3 into a 91 TBI). The little Blazer runs great. Since he has a 5 speed in the old 91 and the 97 S10 Blazer was only available with an automatic.... it used to idle too high during decel and would not settle down until coming to a stop. So a couple of years ago I found a VIN for a 97 4.3, 5 speed, S10 pickup and using my Tech2 I flashed the pickup VIN/OS into my buddie's little Blazer. Problem resolved. Now that I tuned his 04 Yukon Denali he wants me to take a shot at his 91/97 S10 Blazer. What can I do? Newer OS?

Thanks in advance,
Jeff


OK so it was pretty easy to find the answer...0411 ECM upgrade. I guess I was the last to know. I will pick one up right away with the connectors, re-pin, flash it to a VIN I found with his application (2002 S10 4.3/5-speed) and start the tuning:)

Sorry to pull up something so old, but I'm having a similar issue. I am getting the same messege. I have a 97 S10 5 speed, and I am having trouble reading the PCM. It will connect to the scanner and scan, but when I try to read with the editor it doesn't populate the hardware or operating system and I get the message "Unknown Controllers Detected. Specify or Read Again". Then if I pick the only 2.2 option in there, the P11, the editor tells me the same download request message these guys have gotten. I checked to see if it was a supported vehicle even before I bought the truck, and it is. I'm just wondering if I'm doing something wrong or if there is another issue...

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Originally Posted by 1duffman

Sorry to pull up something so old, but I'm having a similar issue. I am getting the same messege. I have a 97 S10 5 speed, and I am having trouble reading the PCM. It will connect to the scanner and scan, but when I try to read with the editor it doesn't populate the hardware or operating system and I get the message "Unknown Controllers Detected. Specify or Read Again". Then if I pick the only 2.2 option in there, the P11, the editor tells me the same download request message these guys have gotten. I checked to see if it was a supported vehicle even before I bought the truck, and it is. I'm just wondering if I'm doing something wrong or if there is another issue...

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Email support or try selecting Big 4L(I believe thats the name) for the ecm type in the drop down.

Big 4L worked, Thank you very much.

so I have a 98 Chevy 4.3l it is connected to the scanner as well and scanning but it is doing the same thing yours is, the vin would not populate so I manually entered it, after that is says Unknown Controllers Detected. specify or read again odd thing is, it is a 98 and when I enter the vin it says 97 4.3l v6 but on my title its 98? ive already chosen all the hardware options still nothing. like I said it is scanning but will not flash or even come up under editor. is it possible that my vehicle is model year 98 but built in 97 with a 97 ecu?

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Originally Posted by rubenh

so I have a 98 Chevy 4.3l it is connected to the scanner as well and scanning but it is doing the same thing yours is, the vin would not populate so I manually entered it, after that is says Unknown Controllers Detected. specify or read again odd thing is, it is a 98 and when I enter the vin it says 97 4.3l v6 but on my title its 98? ive already chosen all the hardware options still nothing. like I said it is scanning but will not flash or even come up under editor. is it possible that my vehicle is model year 98 but built in 97 with a 97 ecu?

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Whats your vehicles vin number?

well called Chevrolet it has all 97 parts, so im guessing it wont work with hP?

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Originally Posted by rubenh

well called Chevrolet it has all 97 parts, so im guessing it wont work with hP?

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Correct.