NAG1 issues

So, car is an 06 300c SRT8; being driven hard it went into limp mode. Codes and dealer led us to believe the conductor panel was bad so plate and connectors were replaced. Cleared all codes and took for test drive, twenty minutes all good then went back to limp mode. Only engages drive after being off for ten minutes then only stays engaged for two or three minutes.

Possibly a bad conductor plate so we order a new Mopar brand valve body which includes conductor plate, sensors and solenoids. Install, refill and same story. No codes this time which makes me think fluid, it will go in gear (reverse and d) every third start or so; no noise no jerks. What am I missing?

Going to need the codes as the plate is very important, was the cup plug replaced?

Paul

Yes, the plug was replaced as well. It is not currently pulling any codes at all. I'll see if the old codes are written down, I know he cleared them.

Edit: Three of the codes had to do with "wrong gear ratios" which with no changes at 108k miles is some sort of sensor issue.

Does it have the correct fluid at the correct level? Are the shifter and transmission controller both functioning properly, and is the transmission controller clean and not full of transmission fluid from the plug leaking? Is the transmission slipping slightly so it goes into limp mode to keep from damaging anything further?

Correct fluid and used the chart coupled with temp to fill it. Shifter seems to be working properly and the plug is ok, it never leaked through. Trans doesn't slip at all, it either engages or it doesn't.

Right now I have 5 quarts of Vavoline +4 in it. I think it may need at least another half a quart. I put the recommended 7 quarts in it once and it leaked everywhere.

Can you use a scanner to check the fluid pressure on those? I believe you can with the Mercedes ones. I was told by someone that works on them that low pressure is another reason that can happen.