2004 hemi pcm replacement
 

I had a problem with a persistent p0058. Sensor and wiring checked out. So I bought the same part # pcm, used from ebay. Arrived today, pulled the battery positive cable, and changed it out.

Good news, check engine light is no more. Starts up fine, then dies as soon as it drops to low idle. No codes, just won't run at idle. Do I have a bad replacement pcm, or is there something I need to do to initialize it ?

Runs fine with the original computer, but the CEL is keeping me from getting an emissions inspection :(

May need to be re flashed.

PCMs are VIN programmed and if there is a mismatch, you will get a code. However, I'm not sure it will be a DTC code.

What is the current code you have now? If it is the same, then the PCM likely isn't your problem.

Maybe my first post wasn't clear.... the original pcm was giving me p0058. I checked the wiring and sensors, all ok... nothing left but the pcm.

The replacement pcm doesn't give me a code.... but it dies as soon as it tried to drop to idle. I don't know what to expect when I just drop a replacement pcm in the truck, should it run?

I expected to have to flash it for inspection. and have a dealer appt scheduled for Wednesday to flash a replacement. Don't really want to pay the dealer to flash a broken one !

You should have bought one from www.solopcms.com where they will sell it at a good price and pre-flashed / VIN matched

Yeah, I could go that way.

But would really like to know if its normal to swap a computer and have it not idle. If its normal, pcm cost plus flashing cost of this one will save me $110 over the solpcms option. I guess I can call the Dealer on Monday and see what they say.

Is it normal? Likely not. It should run fine regardless.

My truck has seen 4 different PCMs, all from junkyards and they ran fine. My truck doesn't have the security system (I think it's called SKIM) so I always made sure my new pcms didn't have it either.

You might want to look into that.

Thanks for the info!

Ebay seller sent me another... just arrived today and I installed an hour ago. Runs fine on this pcm, and no pesky p0058 code anymore.

Only thing, the A/C indicator lamp won't light up.. and the heater mirror indicator is flashing. I read on a forum that if the recirc door is broken, that happens. Mine is removed, I have the replacement but haven't got around to put it in. Perhaps its time to put that door in.

Do I need to have the dealer flash this computer? Its exactly the same number 56029-116AF, which I assume corresponds to the program they put on this thing. My odometer is showing correct mileage, I had assumed it wouldn't because the refurb guys seem to want your mileage... maybe that is for warranty?

No sir

Thank you! Just saved me a bunch of time and some cash !

I guess its off to the inspection station to get my inspection stickers. The indicators seem to be working properly for the ac and mirror heat... maybe it was just an initialization thing since the battery had been disconnected.

I'll drive it a bit and see if anything else pops up.

You may need to drive a couple days so the CARB monitors can complete.

Turns out the vin is recorded in the PCM. To pass emissions, that vin must match the registration. Had the PCM updated with my vin yesterday... I'll the get emissions tested on Monday.

OK, sorry. I was under the impression you got the PCM from a reman place, which usually will input the VIN prior to shipment. My bad. Some emission testing centers, like the ones in my area, don't see the VIN other than when they look at the VIN plate.

No problem, passed emissions today! :)

learning experience...
1. the pcm is on the firewall, not under the fuse box
2. testing the wiring is worthwhile, before buying the second o2 sensor
3. used pcms are a viable option, they have a sticker that identifies the flash version
4. mileage isn't in the pcm, but the VIN is
5. In PA, the VIN is collected as data with emissions testing - you won't pass unless it matches your registration.

Now onto the next issue, persistent ABS problem (no matter which pcm is installed), I think a new thread will appear soon...

Mileage is stored in the PCM, BUT it is changeable with a factory scan tool. The Cluster also logs the mileage separately. It cannot be changed there though. The ability to look at both of these and compare is a valuable tool in discerning ODO tampering.

Good to know, thanks! Hmmm..my scan tool did report the vin, wonder if it'll show pcm version of the mileage....

Curious... when the dealer flashes the pcm, can they make some minimal adjustments to the data/code that is present, or is it fill out a form and flash all entries?

What was strange, is when I got home from the dealer, I checked to see if all tests were complete for inspection - and they were. Seems like it should have taken more than just one 10 minute drive... made me think that the flash didn't clear the CARB monitor data. My scan tool showed the dealer did update my VIN.