Hi,Merry Christmas to all. again new to forum and wanted to see if maybe anyone could give some insight to an issue I have with a 2004 PT Cruiser, 2.4, turbo, automatic. picked this us as a project had a ton of new parts in it but the owner couldnt get it to run right. had the PCM software updated, new turbo, injectors, cat& muffler ect.. motor barely ran and had O2 sensor codes. I sent the PCM for testing or repair and was told non-repairable (melted chip) I replaced it with one off E-Bay and car started and ran but had a miss, and hesitated. started going thru it and found 1 cyl a bit low on compression. pulled the head reseated the valves, replaced the lifters, cams looked great (no lobe wear) and started over. engine ran better but same issues, miss and hesitated. my scanner has basic OBD2 as well as GM and Chrysler programs. OBD shows no codes and all the sensor reading properly(TPS had a slight blip so it was replaced) when I use the chrysler program everything reads but the ECM. I can read the body module, the Trans module but get a NO COMM for the engine module. is there something I might have missed? Please give me any hints/ thoughts anyone might have... would like to find a solution and have a smooth running car. Thanks for any ideas

 

Were the spark plugs and wires replaced? The 2.4l runs best with champion copper plugs. If you replaced the O2 sensors, Bosch is not a good choice, Mopar
, NTK or Denso are best.

Check out the grounds on the left fender; they have a tendency to corrode and are the primary ground point for the ECM.

 

Hi, thanks for responding. when I picked up the PT it had many parts replaced but barely ran. Hears a list
1- timing belt
2- turbo
3- O2 sensors, and cat
4- plugs/wires/coil
5- PCM had software updated to P05033293AJ
Since it showed both O2 faults I replaced both again (didnt help) and sent the PCM out to be repaired and reprogrammed only to be told it was no good (melted chip). replaced it with one from ebay. now it does run ) runs rough and hesitates. I pulled the head reseated the valves, replaced the lifters. checked the timing belt timing several times. getting ready to send the PCM out again thinking its the problem again. also checked fuel pump/injectors all good. all sensors read good on scanner (using OBD mode) but with my Chrysler program PCM shows NO COMM. very confusing

 

Post over on allpar.com. There is a member, Myckee, that specializes in PT cruiser pcm's. Very good reputation and backs his work.

 

Thanks for that info will try that