Hi all,

I need help again for my 2003 Neon. Last year had trouble with the transmission and had to replace it... the car wouldn't move.
After replace, it started to shift roughly... mechanic said the battery was done, needs changed and ECM reprogrammed... did that also.
Two months ago had code P0456 and replaced a leaking evap hose at vapor canister... Now P0441 popped up and went to same mechanic. This time they said they did a lot of tests and everything is pointing to a bad ECM and needs replacement. I am very reluctant that this is the problem. Can this be it ? Could the previous problems (P0456 and transmission issues) have been caused by the ECM ? What will happen if I will just take the car and continue running with P0441 and not replacing the ECM ? I got a quote of $950 and budget is really tight these days.

Thank you !

 

The 03+ have seperate transmission computers, so I don't the think ECM would have caused the transmission to stop working (or a bad battery for that matter; the only thing a bad battery would do is leave you stranded somewhere with a car that wouldn't start at some point).

As for your most recent code, a PCM could be the problem, but not the only one. Of course, it is the most expensive fix so I'm sure that's why that must be the problem.

A code P0441 could mean one or more of the following has happened:

• Bad vacuum switch
• Broken or damaged EVAP line or canister
• Open in PCM purge command circuit
• Open or short in Voltage feed circuit to Purge Solenoid
• Faulty purge solenoid
• Restriction in EVAP solenoid, line or canister
• Corrosion or resistance in purge connector
• Bad PCM

Since the P0456 was an EVAP code too, maybe something wasn't fixed correctly or something else is now being read as faulty since that part was replaced and now working. Only way to know for sure is to test the above things yourself if you can.

If you end up needing to replace the computer, buy one off of eBay or something and replace it yourself. It's what, 4 screws and a plug to remove it?

 

Thank you for your answers !
I was told that they did a lot of tests (about 3 hours) for all the valves and solenoids and everything seems to be working fine, so it must be the PCM.
What do you guys think of getting a PCM from the Internet, something like http://www.allcomputerresources.com/, where they ask for the VIN and the mileage and it comes preprogrammed, so that it just needs replaced ? Are any drawbacks in this approach ?
The mechanic said that there must be installed a new computer that will match the car, otherwise the anti theft system will make the car unoperable... Is this true ? Would the online solution (around $250 as opposed to $950) work ? Did somebody do this on a 2003 Neon SE ?

Thanks again!

 

If you look at that list, there is more than valves and solenoids to be looked at. I'd assume if they were a good, legit shop though, they would have had access to the same information and checked them all...

If they program the computer for the car and such, I'd think $250 vs. $950 would be a great solution. I however know nothing about the anti-theft system on the cars as I don't have it. I can't help on that part. Hopefully someone else will...

 

I would like to do all the tests myself before replacing the PCM, but unfortunately I have no idea where to start. Is there some documentation I can download or some manual that will tell me step by step what needs to be done ?

 

I have a thread around here with links to the 00-02 and 03-05 shop manuals. Download the one you need and have all the information about anything related to your car.

 

Update: took the car back from the mechanic and got scared. I checked the codes, there were tens of codes being thrown!
I thought that the mechanic did some tests and did not reset the codes, so I went and disconnected the negative terminal of the battery to reset the codes. After that, the engine light came back on at the first start, but this time with a different code (P0443). Since then, no other codes appeared. I am thinking to fork another $100 to go to the dealer to diagnose the issue... Any other suggestions I could try before that just to be certain that it is the PCM and not the circuit?

Darthroush, I found your thread and downloaded the manual and I seem to be needed a $300 Miller Special Tool 8815 to diagnose the circuit... Is this really necessary or a simple ohmmeter will work?

 

As for continuing to throw $100 or more on each visit (up to 3 now? So $300 minimum to have them keep telling you it's the PCM), you could have already gotten another PCM. Just my thoughts. I cannot suggest anything more than what the shop manuals say. As for the tool, looking at it real quick, I don't think anything can substitute it as it actually plugs into the controller.