I have just spent the last 30 minutes reading every possible post on the PCM. Everyone says it's great..but what does it actually do? Increase horsepower? Better gas mileage? Lower the balance in my checking account? Ismy warranty voided if I put one in?

Thanks,

Dave

 

First of all, I'll move this to the PCM section..you should do a little more reading...

PCM stands for Program Control Module (GM's name, others call it ECM)...basically it's the ship's computer..Which manages the engine performance and transmission performance along with a few other things vital to the car running properly..

What we the members have done here in mass quanities, is have the PCM re-programmed by PCMforless, as they are able to tweek the factory settings for optimum performance across the board, even calibrate the speedo for whatever tire size you are running, set it for whatever fuel octane levels you want..etc....A bigmust do if you want to get your H3 up and running better with better milage..so yes, it will affect your bank account in that respect.

Here is a picture of the H3's PCM on the firewall behind the coolant tank.

AND NO!..warranty will not be affected.

 

Thanks for the reply. On the gas mileage increase...what would I expect? Currently I have the adventure package (2006), automatic and I get around 13 around town and 16.8 on the freeway. I had a K&N system on it, but mileage went down to around 12, so I took it off. I didn't really care for the sucking sound anyway. I have 5k miles on the vehicle. But maybe increase in HP and a couple of mpg increase might make it worth it.

Dave

 

Should have left the K&N on, you'll get more improvement with it..something must of been different in the way you are driving to lower the mileage, becuase it don't make sensefor you tolose mileage because of it.....But PCMforless can tune for a CAI and Cat-back exhaust orNOT and my personal gains has been about 2 to 3 MPG increase, I do have the K&N CAI and the Gibson Cat-back and I love the combination...gave mea whole bunch more power..I had them tune me for 89 octane.