PCM question
Thread Starter
Heel & Toe
Joined: Apr 2019
Posts: 18
Likes: 0
PCM question
Now I need some answers from someone that are really into the function of PCM boxes. My PCM in my C5 -98 was out of function and had to be replaced, so I got hold of a PCM from a Camaro same year. I know the Camaro doesnt have the drice by wire throttle, so they are obviously not the same.
So, I flashed it with the right software from HP tuners, and the car started, but now in reduced engine mode. The car barely runs, and I need to rev it to keep it alive. The throttle barely opens with the pedal to the floor, and no codes is showing up.
Also, I cannot enter the DTC in the panel.
So, anyone that can guide me here.Are the boxes really not the same, and if so, what makes them different?
// Anders
So, I flashed it with the right software from HP tuners, and the car started, but now in reduced engine mode. The car barely runs, and I need to rev it to keep it alive. The throttle barely opens with the pedal to the floor, and no codes is showing up.
Also, I cannot enter the DTC in the panel.
So, anyone that can guide me here.Are the boxes really not the same, and if so, what makes them different?
// Anders
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,435
Likes: 3,981
From: Cape Coral, Florida
You’re trying to get a PCM from an F Body car to work on a Y Body...doubt it’s going to work... like you said the Camaro is not “drive by wire” and the Corvette is !!!...that’s why your throttle isn’t working....there are 2 serial data wires that go from the TAC module to the PCM...where are your 2 wires going to run to your new PCM ??...it’s not there !!...you’ve posted this issue before so the best thing for you is to get a 98 PCM and be done with it !!
Last edited by C5 Diag; May 14, 2019 at 02:01 PM.
Thread Starter
Heel & Toe
Joined: Apr 2019
Posts: 18
Likes: 0
I was not really asking for opinions, or what someone might think based on no experience.
I want to learn more in this topic becasue I'm curious... The box took the flashing process with the HP tuner just fine, and I want to know if there is some difference in the OS or so...
Please, if someone has the answer I really want to know it...
// A
I want to learn more in this topic becasue I'm curious... The box took the flashing process with the HP tuner just fine, and I want to know if there is some difference in the OS or so...
Please, if someone has the answer I really want to know it...
// A
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,435
Likes: 3,981
From: Cape Coral, Florida
I was not really asking for opinions, or what someone might think based on no experience.
I want to learn more in this topic becasue I'm curious... The box took the flashing process with the HP tuner just fine, and I want to know if there is some difference in the OS or so...
Please, if someone has the answer I really want to know it...
// A
I want to learn more in this topic becasue I'm curious... The box took the flashing process with the HP tuner just fine, and I want to know if there is some difference in the OS or so...
Please, if someone has the answer I really want to know it...
// A
Last edited by C5 Diag; May 14, 2019 at 02:17 PM.
Thread Starter
Heel & Toe
Joined: Apr 2019
Posts: 18
Likes: 0
Curious, for what is a opionion worth when it comes to technical advice, I thought you where the experts? If this forum is all about opinions, then I'm really getting scarred!
Also, ofocurse you can find this answer, and no it's not a question of GM proprietary information, it's all about beeing curious...
Anyone else that have the answer, and if there might be some differences in the OS or so?
// A
Also, ofocurse you can find this answer, and no it's not a question of GM proprietary information, it's all about beeing curious...
Anyone else that have the answer, and if there might be some differences in the OS or so?
// A
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,435
Likes: 3,981
From: Cape Coral, Florida
Curious, for what is a opionion worth when it comes to technical advice, I thought you where the experts? If this forum is all about opinions, then I'm really getting scarred!
Also, ofocurse you can find this answer, and no it's not a question of GM proprietary information, it's all about beeing curious...
Anyone else that have the answer, and if there might be some differences in the OS or so?
// A
Also, ofocurse you can find this answer, and no it's not a question of GM proprietary information, it's all about beeing curious...
Anyone else that have the answer, and if there might be some differences in the OS or so?
// A
Last edited by C5 Diag; May 14, 2019 at 02:33 PM.
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Thread Starter
Heel & Toe
Joined: Apr 2019
Posts: 18
Likes: 0
Yes, the compatability of the operating system, and if there might be some small differences not taken care of by the Flashing. Still, the boxes are by looks the same, flashing works just fine for the Corvette -98 tune, and it starts. Just want to know if there is something before I move on, and especially what it is without guessing.
// A
// A
Melting Slicks
Joined: Sep 2008
Posts: 3,127
Likes: 799
From: Espanola New Mexico
They have already explained that your Camaro PCM has no output "no wires" to actuate the throttle body blade. There is no OS to speak of, the corvette has various modules that communicate together on a serial line. Do your self a favor and get the correct pcm.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
SURE,,, It starts. LOL! But you have already diagnosed and answered your OWN QUESTION.
"So, I flashed it with the right software from HP tuners, and the car started, but now in reduced engine mode. The car barely runs, and I need to rev it to keep it alive. The throttle barely opens with the pedal to the floor, and no codes is showing up."
The PCM is in REDUCED ENGINE POWER because there is NO CONTUNITY between the PCM and the with the critical Throttle Control Circuit. That's what Reduced Engine Power mode is!! GM designed the throttle control circuit to enter Reduced Power mode if there is ANY disparity between what the throttle peddle position is and the actual throttle is.
Thus "The throttle barely opens with the pedal to the floor," Its a designed SAFETY feature!
The F Body has an EGR Valve that the Y Body DOESNT HAVE, does the F Body have the same size injectors as the Y body? That value is written to the PCM and must be manually changed if the injectors are different.
The MAF air grams/sec are most likely way different for the F-body tuning as compared to the Y body due to the difference in air box and air ducting. The MAF values probably needs to be tuned to function properly.
SO, you flashed the PCM.. Did you tune any of the other critical operating parameters that need to be changed between a Y body and an F body tune??.
The REDUCED ENGINE power is most likely NOT solvable unless you tune the PCM to operate without a Throttle by wire system and remove ALL the throttle by wire stuff from the C5. Switch over to a cable actuated throttle!!!!!
Is the IPC functioning normally? Can you clear the messages in the DIC when you press reset. Can you use HP Tuners to read the DTCs????
Bill
"So, I flashed it with the right software from HP tuners, and the car started, but now in reduced engine mode. The car barely runs, and I need to rev it to keep it alive. The throttle barely opens with the pedal to the floor, and no codes is showing up."
The PCM is in REDUCED ENGINE POWER because there is NO CONTUNITY between the PCM and the with the critical Throttle Control Circuit. That's what Reduced Engine Power mode is!! GM designed the throttle control circuit to enter Reduced Power mode if there is ANY disparity between what the throttle peddle position is and the actual throttle is.
Thus "The throttle barely opens with the pedal to the floor," Its a designed SAFETY feature!
The F Body has an EGR Valve that the Y Body DOESNT HAVE, does the F Body have the same size injectors as the Y body? That value is written to the PCM and must be manually changed if the injectors are different.
The MAF air grams/sec are most likely way different for the F-body tuning as compared to the Y body due to the difference in air box and air ducting. The MAF values probably needs to be tuned to function properly.
SO, you flashed the PCM.. Did you tune any of the other critical operating parameters that need to be changed between a Y body and an F body tune??.
The REDUCED ENGINE power is most likely NOT solvable unless you tune the PCM to operate without a Throttle by wire system and remove ALL the throttle by wire stuff from the C5. Switch over to a cable actuated throttle!!!!!
Is the IPC functioning normally? Can you clear the messages in the DIC when you press reset. Can you use HP Tuners to read the DTCs????
Bill
Burning Brakes
Joined: Aug 2017
Posts: 958
Likes: 177
From: Newark Delaware
You've had two of the preeminent electrical gurus of C5s respond to your question. I dare say, no better answers will be coming your way. Where is 8Vette7 when you need him to properly 'educate' the thread starter.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Melting Slicks
Joined: Jan 2009
Posts: 3,275
Likes: 739
From: Miami FL
Drifting
Joined: Mar 2017
Posts: 1,483
Likes: 343
From: Long Island New York
He bolted about a year ago, or longer. He was one of the first to help me out.
Since he took down many of his post and all that remains is quoted from his posting.
He must of bumped heads with someone or something here
Since he took down many of his post and all that remains is quoted from his posting.
He must of bumped heads with someone or something here