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In theory no. But ive seen wierd things if totally incorrect/mismatching calibrations are uploaded to nvrams so i'll say highly unlikely instead

The big difference is you need to erase a flash chip before writing it, with an NVRAM it just writes over the top so aborting halfway is normally no problem. On a flash PCM aborting halfway leaves half the cal blank which can cause the PCM to crash when trying to use the data. If this happens it can be hard to get it to reconnect to a PC.

I think you need to revisit the bench PCM before trying to flash a PCM. Something is not right with the in car setup, with TunerPro also not being able to log it then its a timing issue with the bus chatter or a sus ALDL interface. Id be putting money on that its a timing issue as you can read the chatter ok.

VL400 wrote:The big difference is you need to erase a flash chip before writing it, with an NVRAM it just writes over the top so aborting halfway is normally no problem. On a flash PCM aborting halfway leaves half the cal blank which can cause the PCM to crash when trying to use the data. If this happens it can be hard to get it to reconnect to a PC.

I think you need to revisit the bench PCM before trying to flash a PCM. Something is not right with the in car setup, with TunerPro also not being able to log it then its a timing issue with the bus chatter or a sus ALDL interface. Id be putting money on that its a timing issue as you can read the chatter ok.

OK ill try get the bench setup working. i stll cant even get it to pick the pcm up so somethings not right there. ive followed that diagram and changed the wiring to reflect the changes that needed to be made but still no connection.

Power unit is just a 120w 12VDC 10A unit.

I have 12v at all 12v connections a pcm, earths at all earth points. ignition on a switch. still doesnt pickup PCM. i know the car will pick it up but bench wont.

I reckon there is another issue with that diagram, your not the only one it hasnt worked for. I reckon check against other pcm wiring docs and see if you can find whats wrong/missing.

Ok I have some success!!!!

So I think what is different from the post I went from and my setup is I have connected all earths from the OBD port, also added the 12v from THE OBD to 12v at battery! We have a successful bin read and write!

I may write another how to post for the wiring that makes it easy for others as whenever I wanted to find the post regarding wiring the flash PCM I could never find it!!

I still have problems with the in car connection but won't worry about that at them moment!

Yes, you are the car side of the obd remember, you cant take ground from there, you supply it to there from your loom. The 12v pin at the obd is usually a good idea to have so the port has power and signal for whatever purpose you need less but the aldl interface does not use it. It uses ground and ALDL for signal and powers itself from the usb plug from the computer. Powering it this way saves the virtual com port dropping out and driver reload as you key off and on the car.

antus wrote:Yes, you are the car side of the obd remember, you cant take ground from there, you supply it to there from your loom. The 12v pin at the obd is usually a good idea to have so the port has power and signal for whatever purpose you need less but the aldl interface does not use it. It uses ground and ALDL for signal and powers itself from the usb plug from the computer. Powering it this way saves the virtual com port dropping out and driver reload as you key off and on the car.

I might actually check if the cars OBD earth pins are actually functioning correctly. ive had absolutly no problems with reading / writing to this PCM on the bench, but big problems in car. I will try with a few different timeout settings. Would i just be trying different "wait for silence" times or the other time outs and delays?

The chatter you posted looks ok so the electrical wiring seems ok. I would suspect one of the devices on the aldl bus in the car has degraded and transmitting with the wrong timing causing a collision with the silence chatter request which then fails and its all over from there. Yes try different timing settings. Maybe wait for less ms of silence.

Does your BCM have a different supply fuse than your PCM? If so, you might try pulling the BCM fuse. Worth a shot.

Joe.

hsv08 wrote: I have connected all earths from the OBD port

Ahh... that is what was causing alot of problems.