P59 ECU 04 yukon xl READ VCM timed out

Hey, everyone. I?m new to tuning and using hptuners for the first time. I?m building a fresh motor for my 04 Yukon and I?m familiarizing myself with everything ahead of tuning for larger injectors and a bigger cam.

Using my MacBook Air running windows 7 in bootcamp the read vcm operation times out after 20 minutes and 15% complete. Using my wife?s brandy new Lenovo on windows 10 I was able to read the VCM but it took 70 minutes!! I had a jumper pack hooked up to keep the battery from getting too low. At some point the voltage dropped to 11.8 so I scrambled to grab my 1amp trickle charger to assist. (I know it?s not recommended to have a charger going at the same time as a read or write, but low voltage seems worse.)

Now that I have the stock file saved and ready for tweaking, I?m weary of problems writing to the PCM. My understanding is that this PCM should take 5 minutes read... It previously had a diablosport tune but I put the stock file back in to read the VCM.

Any assistance is appreciated. I?m not sure if this is a question best left to the HPtuners support team.

Dan

Does the vehicle have a factory radio and alarm system or is there anything aftermarket hooked up?

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Originally Posted by 5FDP

Does the vehicle have a factory radio and alarm system or is there anything aftermarket hooked up?

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Factory radio, and a factory alarm, though an aftermarket remote start is installed.

I'm not sure if that would cause any problem. I just know that the radio's/alarm can and if there is an aftermarket chime adapter installed.

Does anything change if you try to read the computer in low speed and not high speed??

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Originally Posted by 5FDP

I'm not sure if that would cause any problem. I just know that the radio's/alarm can and if there is an aftermarket chime adapter installed.

Does anything change if you try to read the computer in low speed and not high speed??

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Thank you for your replies. I?d imagine that low speed would take even longer, but it?s worth a shot to see if there is a positive change.

Is there any consequence to aborting the read if it ends up taking a very long time?

Any suggestions for maintaining the battery voltage if it takes as long or longer?Is there a preferred battery charger that won?t potentially introduce a/c voltage?

I suppose I can always hook up a running car with some jumper cables if needed...

Aftermarket remote starts will tap into the purple wire on the ALDL plug to disable VATS to start the vehicle without a key in the ignition. Find the wire and disconnect it while reading and flashing.

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Originally Posted by 2xLS1

Aftermarket remote starts will tap into the purple wire on the ALDL plug to disable VATS to start the vehicle without a key in the ignition. Find the wire and disconnect it while reading and flashing.

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Ah-ha, yes I do have a wire hooked to the serial data wire on the ALDL. I’ll remove it and see what happens. Thank you for the reply.

Ok success, but not as I was expecting.

Removing the remote start wire from the ALDL serial data wire improved things with my macbook air but did not solve the 70 minute READ VCM problem. Atleast with the macbook it didnt time out after 15%.

The solution, uncheck the box for High speed. Using "slow speed" I was able to read the VCM in 14 minutes on both laptops. The progress percentage increased smoothly and consistently and the elapsed time remaining remained mostly accurate along the way.

I suppose there isnt anything wrong with the PCM and im good to go writing calibrations. With the ALDL wire disconnected of course.

Thanks for your assistant.