TwoBob

Hello. I installed a PCM (Overkill) in my 2005 Monte Carlo LT today and I was expecting to do a security relearn and a case relearn. To my surprise, it was plug-and-play, as in I didn't have to do any of those things. The car just started right up after I reconnected the battery. I drove it around for about half an hour, and the car drives really good. I've read numerous times that you need to do a case relearn after installing a PCM. My question is, if the car is running ok, do I really need to do it? Or, I should ask, am I harming anything on the car if I don't get it done? Any help would be appreciated.

tech2

case relearn means what? the only relearn that chevy require are theft deterrent relearn and crankshaft variation relearn.

so did you send them the pcm out of this car and they tune it or did they send you a pcm from their stock?


How do you like it. I am thinking about trying one of their tunes for my gtp.

TwoBob

Sorry, I should clarify. Its called a crank censor position relearn. The pcm came with instructions saying I should get it done afterwards, since there would be a check engine light after the install... Except there's no check engine light. I'm assuming all is well, but I wanted to check the forums to see if it was needed.

They sent me a pcm from their stock. I'll get my core charge refunded as soon as I mail them off my stock pcm. I got the 91± octane tune, and I'm enjoying it. I've only driven it for about half an hour today, but immediately I can notice the difference. It's a lot more responsive, the shift points are nice, and the transmission shifts are CRISP. I can feel the car jump forward a bit after shifting into 3rd, which it didn't do before. The 3-to-1 shift is awesome. I can only imagine how much better the tune would be if I had mods done prior to the install. This will definitely do for now

tech2

a lot of people think Will has the best 3800 series tunes.

they must have programmed the pcm to your vin. the theft deterrent release password must of been learned at key on.

the crankshaft variation relearn is required for the misfire monitor. If not relearned the misfire monitor may set false misfire dtc...usually, they set at high rpm. Each cks sensor is unique and its signal must be learned to the pcm. Anyone with a full function scan tool can perform this procedure where the pcm learns the cks sensor.

TwoBob

Just curious, what would happen if the misfire monitor sets a false misfire? I gather that you're saying it's bad if I don't get get it relearned, but I'm just curious.

Thanks for the reply

tech2

not sure if anything bad will happen. I do not know what strategy the pcm will default to during a misfire condition.

it will be a red herring if you try to diagnose for a misfire that is not actually occurring.