huge problem after PCM update / calibration

yazan

Well-Known Member
i go to a local store for programing / tuning to update the pcm / calibrate , many friends done this before and got some good results , enhanced fan clutch , better ac at idle
, less overheating due to enhancing the fan clutch response and many other results
So the guy who handle the tech2 and hp tuners he check the list and verify the vin number
After starting the progress he got error and he cant do the update again , I don’t know what is the reason behind the error , but the problem he cant start the engine or even communicate with the pcm via tech2
Every time he try to communicate he got connection error
The engine wont start
He can't do restore or reflash
The he told me my pcm damaged , so I go to the salvage / junk yards
After installing the used pcm , the engine start with high rpm then engine stall
Now I am in a big trouble
What happened to the oem pcm and what can cause the damage ?
What is the solution except going to the stealer ship
Iam really disappointed
Any help is deeply appreciated


GM Vehicle Calibration Information VIN: 1GNET16S326111483 Controller: PCM/VCM Powertrain/Vehicle Control Module Calibration History for: Operating system Part Number CVN Bulletin # Description 12587430 0000D75E - New calibration to improve idle stability 12579238 N/A - Operating system software replaces 12571911, 12213305 and 12575262 Calibration History for: Engine Part Number CVN Bulletin # Description 12591954 0000FF37 - New calibration for diagnostic enhancements 12587441 00003A8F - New calibration to improve idle stability 12583556 000033BA - New calibration to correct cold idle fluctuation at altitude and/or warm hesitation on acceleration 12579249 0000AF11 - Calibration to correct cold start idle surge and hesitation 12576999 0000ABC0 - Engine calibration Calibration History for: Transmission Part Number CVN Bulletin # Description 12583717 0000F076 - New calibration to correct cold start/shift problems 12579259 00007A11 - New calibration to improve feel of 1-2 upshift 12573458 0000AE39 - Transmission calibration Calibration History for: Speedometer Part Number CVN Bulletin # Description 9351579 0000A898 - Speedometer calibration Calibration History for: System Part Number CVN Bulletin # Description 12596395 0000ED28 - New calibration to address customer complaint of overheat condition. 12587759 000030A6 - Enhanced Calibration for Cooling Fan Noise Reduction 12583726 00000E9A - New calibration for improved fan control 12577539 0000CB8A - System calibration Calibration History for: Electronic Throttle Control Part Number CVN Bulletin # Description 12571574 00003BC9 - Electronic throttle control calibration Print Close
 

AtlWrk

Well-Known Member
I don't know enough about the programming process to guess what went wrong the first time.

You might be having a problem with the replacement PCM simply because of a dirty throttle body (search here for the article on "How to clean your throttle body"). After the PCM has been disconnected long enough to reset it, a dirty throttle can cause rough idle and stalls, particularly with the AC on.
 

Mounce

Well-Known Member
I was also gonna say that's because of your dirty throttle body. If you've never cleaned it, it likely looks like this...

uploadfromtaptalk1429286805084.jpg

Other than that, program the new PCM with your vin and have the tuner do the necessary relearn(s) and tune it and you should be good to go.
 
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yazan

Well-Known Member
thanks for the updates and replays guys iam really appreciating

i got some help from our member here he lives in saudi arabia , he offers a help , he have pcm he will send it to me , he replaced the engine with pcm installed m so the old pcm he keep it for spare , but we are afraid it will got damaged

so guys do you thing the tb is related to not start with security lights on and no transmission shifter position marker?

thanks again


the 2nd question is : there is no way to restore the oem pcm ?
 

kickass audio

Well-Known Member
do you happen to have any aftermarket devices like a remote start installed? I know when I went to have my PCM upgraded just for the hell of it when it was at my local shop they couldn't get the upgrade to work. They then disconnected the bypass module for the passlock that makes the remote start run and it allowed the PCM and BCM to get upgraded. Basically, anything that ties into the data line on your truck will screw up this procedure.
 
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yazan

Well-Known Member
Actually I see him using tech2 and hp tuners in the progress ,
While he is updating and got the error , there is a msg about removing fuse number 6 and 51 in the rear fuse box
Do you thing pcm4less help me out in this ?
 

Mounce

Well-Known Member
You can keep the junkyard PCM and use it for tuning and stuff. It'll work the same as the one you said you were gonna get from the other member.
 
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yazan

Well-Known Member
kickass audio said:
do you happen to have any aftermarket devices like a remote start installed? I know when I went to have my PCM upgraded just for the hell of it when it was at my local shop they couldn't get the upgrade to work. They then disconnected the bypass module for the passlock that makes the remote start run and it allowed the PCM and BCM to get upgraded. Basically, anything that ties into the data line on your truck will screw up this procedure.
sorry did not read your replay ... i think yes , the first owner did, but when i bought the TB i don't know that there is a remote start device installed because there is not remote key , until i got some problem so i start checking around and found that device installed under the steering wheel column, removed the device from the sockets / connectors , without removing the wiring harness , and every thing go fine ,,, that was 3 years before , no problems until now ,

the question now , can i install another pcm without the need of programming ? or at least tech2 ?
 

Mooseman

Moderator
You can install any PCM from a same year truck and it will work after a security relearn, which you can do yourself:

1. Attempt to start the truck by turning the key to the Start/Run position. Try to crank the vehicle.
2. Observe that the vehicle fails to start and the security light is illuminated.
3. Release key to the ON/RUN position (not the ACC position or OFF)
4. Allow the vehicle to sit with key in the ON/RUN position for no less than 11 minutes. Security light will turn off after this.
5. When the light goes off, turn key to OFF position and allow the vehicle to remain in the OFF position for 10 seconds.
6. Repeat #1-#5 for four cycles or until vehicle starts.



That's how I got myself a spare PCM, worked perfectly.
 
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yazan

Well-Known Member
Mooseman said:
You can install any PCM from a same year truck and it will work after a security relearn, which you can do yourself:

1. Attempt to start the truck by turning the key to the Start/Run position. Try to crank the vehicle.
2. Observe that the vehicle fails to start and the security light is illuminated.
3. Release key to the ON/RUN position (not the ACC position or OFF)
4. Allow the vehicle to sit with key in the ON/RUN position for no less than 11 minutes. Security light will turn off after this.
5. When the light goes off, turn key to OFF position and allow the vehicle to remain in the OFF position for no less than 30 seconds.
6. Repeat #1-#5 for four cycles or until vehicle starts.


That's how I got myself a spare PCM, worked perfectly.
thanks guys , very helpful info Mooseman

the pcm that from the other member here , is for envoy 2003 .. so it will not work for my 2002 tb ?! without complicated tech2 work ... iam still waiting for that pcm shipped already .



i found a seller on ebay said :





This is a good working used engine computer for the:

TRAILBLAZER 02 Electronic Control Module; (LH eng)
TRAILBLAZER EXT 02 Electronic Control Module; (LH eng)

Will be flashed with the latest GM program using your VIN
(Vehicle Identification Number)

No core needed

Lifetime warranty

Unit ships same or next day with free Priority Mail in the US

Return for any reason with no restocking fees

Please remember to send a separate email with VIN for fast service
VIN can be found on driver's door sticker or insurance card
Please count out the 17 digits when sending


Note:
The anti-theft system may need to be reset. This takes thirty minutes, no tools are needed, and instructions will be included. In some cases the P0315 or P1336 code will come up after install and relates to the crankshaft variation relearn procedure needing done. A scan tool is needed for this procedure. The vehicle will run and drive but the service engine light might not go off until the procedure is done.
is that true i can drive the car without crank shaft position relearned ?


my problem is going difficult because i live in a small town , the workshop in about 250 km far about me ,
stealer ship refuse to accept any parts from junkyard or used to install ,,,
so i have to stay at workshops they have tech2
 

Mooseman

Moderator
You can drive it but you may get a code and CEL about the crankshaft angle. This is what we refer to a CASE relearn and you will likely need it to get rid of the CEL. Can be done using a Tech2. It will not cause any problems driving it like that unless you have to pass an emissions test.

As far as the stealership is concerned, just show up, say nothing about the PCM and say that for some unknown reason, you are getting this code. There is no VIN on the PCM itself so they won't know any different. It can happen if the crankshaft sensor is disturbed or changed. They'll do the relearn and happily take your money.

The differences between 2002 and 2003 may be minimal but could be enough to cause problems. As far as I know, the only difference between the two is the low oil level sensor but sometimes there could be other small differences to cause issues. It's always recommended that the PCM come from the same year be used. Checking car-part.com, when searching for a PCM for a 2002, it lists only 2002 year trucks.
 
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yazan

Well-Known Member
Mooseman said:
You can drive it but you may get a code and CEL about the crankshaft angle. This is what we refer to a CASE relearn and you will likely need it to get rid of the CEL. Can be done using a Tech2. It will not cause any problems driving it like that unless you have to pass an emissions test.

As far as the stealership is concerned, just show up, say nothing about the PCM and say that for some unknown reason, you are getting this code. There is no VIN on the PCM itself so they won't know any different. It can happen if the crankshaft sensor is disturbed or changed. They'll do the relearn and happily take your money.

The differences between 2002 and 2003 may be minimal but could be enough to cause problems. As far as I know, the only difference between the two is the low oil level sensor but sometimes there could be other small differences to cause issues. It's always recommended that the PCM come from the same year be used. Checking car-part.com, when searching for a PCM for a 2002, it lists only 2002 year trucks.
very very helpful and rich of info that i learned ,,,, thanks is not enough

so tech2 cant do the job for the deference in models ? Wednesday i will install that envoy 2003 pcm , in the workshop they have tech2 & hp tuners ...
and will see what will happen m otherwise if the problem not solved . then i will order from pcm of nc , i emailed him for price inquiry


sorry for the too much questions ,,

thanks , iam deeply appreciating
 

Mooseman

Moderator
I'd suggest contacting Jeremy at Lime-swap instead for info on a tune or swap. Much cheaper and very friendly as well as a GMT Nation member.

You can try using the 2003 PCM in your 2002. Might work. Try doing the security relearn and see if it will at least work stock. Your oil level sensor will definitely not work then since they eliminated that option in 2003.
 

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