ECM questions

anyone know if the ECM can be swapped out from one car to another?
i see service part number 16214399 all over.. i see a used one for $25.. maybe this would help with my sort of intermittent VATS issue where the car has refused to start even when waiting and the bypass resistor being in place..
thanks for any help..

Yes the PCM can be swapped between cars. 94/95 are OBD1 while the 96 is OBD2 and not compatible with the other two. Unless they are from identical cars the tune from your car will have to be uploaded to the swap PCM.

That said, VATS is controlled by its own ECM. The system is trash and should be eliminated from every B Body. Info on how to do so is readily available at ISSF among other places.

i agree, VATS is ^%$@!

ISSF..??

will look at the youtube instructions again, i just don't want to BRCK the ECU's in my 95's..

thanks

billmorrow wrote:

i agree, VATS is ^%$@!

ISSF..??

will look at the youtube instructions again, i just don't want to BRCK the ECU's in my 95's..

thanks

www.impalassforum.com  THE website for B Body info. This longroof website only came to be after a spat between an ahole mod that is no longer there and some wagon owners that probably aren’t here any longer.

Deleting it requires a laptop, an ALDL cable and a couple of free programs. Once that is done you unplug the VATS module and connect two wires together with a paper clip. Doing that grounds the relay and bypasses the system forever. I pulled the module and tossed it into the trash also connected my wires with a butt connector.

"VATS module"..?
is that a relay or..?
and i have looked under the dash but can not see an OBD1 plug on my 95's, anyone know where i might look..?
thanks

billmorrow wrote:

"VATS module"..?
is that a relay or..?
and i have looked under the dash but can not see an OBD1 plug on my 95's, anyone know where i might look..?
thanks

odb1 plug should be below and to the right of the steering wheel (over the gas pedal hanging off the bottom of the dash).

Vats module is an ECM mounted inside the dash. Mounted above the parking brake pedal area. The relay is someplace else, passenger side behind the kick panel I believe. Never looked for it since it can be grounded at the module plug.

94Woody wrote:

Vats module is an ECM mounted inside the dash. Mounted above the parking brake pedal area. The relay is someplace else, passenger side behind the kick panel I believe. Never looked for it since it can be grounded at the module plug.

thank you..
i spent many many hours looking for the apparently failed power windows cutoff relay in my all original '70 eldorado..
never did find it, was finally told it is above the parking brake but inaccessible so surrendered and installed a power line around so the windows work without need of the ignition key..
i hope the VATS crap is not similarly situated..  

one more question: how to clear codes so as to know if a code is a NEW or current code..

hello after a month or so..
i replaced the ECU SERV NO. 16188051 in my '95 RWM (when it refused to start displaying the VATs light on the dash with:
my spare ECU, SERV NO. 16214399
car started right up and VATs light is not on..
the car seems to run ok moving it in the driveway..
i see ads all over ebay for rebuild ECUs they want the VIN..
so my questions are REALLY need the VIN and can i use the car as it is with the replacement ECU?
thanks

Yes they need the vin so they are sure they put the correct calibrations in the replacement PCM. Buick wagon is different than the Chevy because of its ability to display fault codes in the HVAC controls among other differences from the Chevy.

These LT1 cars don’t have an ECM like the older cars. They have a PCM, Powertrain Control Module because it controls the engine and transmission together and doesn’t have a removable EProm that is is programmable.

In the early days of ECM, they were a target of thievery, like cat convertors are today. Reputable shops required the VIN to combat the resale of ill-gotten units.

thank you for the info,
today, friday, i put a newer, used ECM, i picked up for $25, with the original knock module from the '95 IN the 95 and it seems to like it..
starts right away, so far..
runs well, shifts correctly, will road test more in the next days..

not sure where the vin is stored or why mileage data should be stored in the ECM when there is a mechanical mileage clock in the dash..

just what exactly IS this knock module and why is it called that..?
when knocking and gas engines are words used together i think pre-ignition from too low octane gasoline..

It’s not that the VIN is stored the VIN tells them what base file to use when the PCM is being programmed. The PCM controls everything in the Powertrain (hence the name) and there was more than one gear set used in the multiple B Body cars, transmissions have different programs, etc. Put the wrong program in and stuff isn’t going to work correctly. Buick odometer is mechanical while the Caprice/Impala is digital. Funny thing is the mileage is only saved in that digital module and cannot be changed.

The knock sensor is basically a microphone that is listening for knocking sounds. The LT1 version is setup for that specific engine, standard steel valve train, cast iron manifolds, etc. Adding something like noisy roller rockers will trick the module into hearing a knock and mess with timing. So people would install the LT4 module because it is setup for for performance and will filter out that noise.

Good job finding a $25 PCM. Last one I bought at LKQ cost me almost $100.

94Woody wrote:

It’s not that the VIN is stored the VIN tells them what base file to use when the PCM is being programmed. The PCM controls everything in the Powertrain (hence the name) and there was more than one gear set used in the multiple B Body cars, transmissions have different programs, etc. Put the wrong program in and stuff isn’t going to work correctly. Buick odometer is mechanical while the Caprice/Impala is digital. Funny thing is the mileage is only saved in that digital module and cannot be changed.

The knock sensor is basically a microphone that is listening for knocking sounds. The LT1 version is setup for that specific engine, standard steel valve train, cast iron manifolds, etc. Adding something like noisy roller rockers will trick the module into hearing a knock and mess with timing. So people would install the LT4 module because it is setup for for performance and will filter out that noise.

Good job finding a $25 PCM. Last one I bought at LKQ cost me almost $100.

I think the VIN number is in the PCM someplace, although it probably goes in with the tune. For instance, I have found that when I put in backup PCM I have on shelf, like I did to test it after purchase, the DST tuner used up another of the applications that came with the tuner. HPtuner does the same thing for the later models, it appears. A Buick PCM in a Chevy would also keep the DST tuner from even connecting as many of us have run across. I think the older predecessor TunerCats didn't have the Buick issue, though, or keep track of applications it was used for.

booster wrote:

94Woody wrote:

It’s not that the VIN is stored the VIN tells them what base file to use when the PCM is being programmed. The PCM controls everything in the Powertrain (hence the name) and there was more than one gear set used in the multiple B Body cars, transmissions have different programs, etc. Put the wrong program in and stuff isn’t going to work correctly. Buick odometer is mechanical while the Caprice/Impala is digital. Funny thing is the mileage is only saved in that digital module and cannot be changed.

The knock sensor is basically a microphone that is listening for knocking sounds. The LT1 version is setup for that specific engine, standard steel valve train, cast iron manifolds, etc. Adding something like noisy roller rockers will trick the module into hearing a knock and mess with timing. So people would install the LT4 module because it is setup for for performance and will filter out that noise.

Good job finding a $25 PCM. Last one I bought at LKQ cost me almost $100.

I think the VIN number is in the PCM someplace, although it probably goes in with the tune.  For instance, I have found that when I put in backup PCM I have on shelf, like I did to test it after purchase, the DST tuner used up another of the applications that came with the tuner.  HPtuner does the same thing for the later models, it appears.  A Buick PCM in a Chevy would also keep the DST tuner from even connecting as many of us have run across.  I think the older predecessor TunerCats didn't have the Buick issue, though, or keep track of applications it was used for.

sigh..

and there DOES seem to be some uncertainty when this RMW shifts..

and i could change the VIN in this new to me PCM/ECM if there was some software application i could put on a laptop and talk to the PCM/ECM using the OBD1 plug i have but the only such apps i see online cost many hundreds of $$$ OR i can buy a replacement ECM from flashmasters who will program the VIN all for $300..
so what to do, maybe there is a way to reset the ECM..?

i guess i can always sell these spare ECM's and just use the flashmaster guys ECM..

apologize for all these disconnected thoughts and hope for some enlightenment..

to put an end to this topic, here, i threw in the towel and bought, from garret tuning a reprogrammed, with the VIN, ECM. who promise to ship tuesday for a LOT of $$, more than flagship one wanted but then flagship one strung me along for 10 days doing nothing, just kept saying, it will be shipped in 3 business days.. business days..! really meaning not today or tomorrow or any time, just sometime which turned out to be never..

To follow up, you can read more about how to read and write the correct calibrations (and custom tunes) to your PCM here. I also use eehack for datalogging and diagnostics and it's a lifesaver.

sherlock9c1 wrote:

To follow up, you can read more about how to read and write the correct calibrations (and custom tunes) to your PCM here. I also use eehack for datalogging and diagnostics and it's a lifesaver.

thank you, i'll go look..
meanwhile, garret tuning overcharged me for the ECM i got from them, their web site lists it for about $350 (way high price for a $30 salvage ECM) and $100 to program out the VATS capability..
all i wanted was for the car to start and shift correctly which it now does but looking at the fault code list i see many old fault codes from the previous salvage car this ECM came from..

no time yet to go back to the garret tuning people and complain..