RLSebring

I suddenly cannot read the PCM. I just wrote some tune updates a few days ago and everything was working fine. Last night went out to make a change or 2 and could not read or write to the PCM.

HP Tuners wouldn't connect so I tried my trusty code reader and after about 30 seconds it gives me an error message. The message is "error".

I checked the fuse and is good. Cigar lighters is working and when I first plug in the code reader the lights flash but go off. Tuners has the green light with just the OBD2 plugged in, not the USB.

I have checked everything I know to check. You guys have any input. The car cranks and runs fine.

Mez

Strange. Usually if the MPVI has a green light, the fuse would not be the problem. I had a similar problem but no green light on the MPVI. It turned out to be a fuse in the panel under the passengers side carpet.

Perhaps the cable with the serial connector to the MPVI has a bent pin. Other than that, I am out of ideas. Since you code reader has an 'error' my guess it is something to do with the OBDII connector under the dash. Sorry.

RLSebring

Thanks for the response. I had forgot I posted here also. After last night and mostly of today it decided to start working again. I had ran through all I knew to check. Even had power and ground at the plug.

Someone on the other thread mentioned it might just have to cycle several times. I took a break this afternoon and ran some errands must have stopped and started the car about a dozen times.

While out I plugged the code reader in and it worked fine. I got home and plugged the laptop in and worked perfect as well. I hate these situations of not knowing what was wrong and not knowing why it started working again.

Tag_sk

I have the same issue with my 05 c6. My code reader says it is unable to connect. I have taken the car to the dealership and they hook up there Tech2 and it works fine, then I can connect with my code reader for a week or so then the problem is back.

seevi

Are you using HPT 2.2 or the Beta. I had that problem several times today. I just unplugged the USB, waited a couple of seconds and plugged it back in. After the PC recognizes the USB, I can reconnect.

spdmn75

The OBD2 fuse is under the passenger seat mat its the rear fog/ALDL fuse.

yonson

I haven't had this problem with the HP Tuners interface but with the SCT programmers you have to put the car in ACC mode before plugging the programmer into the OBD II connector, you might try this and see if it helps.