I recently purchased a 2005 PT Cruiser Limited (125K miles). It needed some general maintenance and a few repairs so I replaced the timing belt and water pump. I also replaced the turbo center section, the radiator, and the lower left front control arm. The engine runs well, but I am receiving weird trouble codes. They are coming in pairs of two. Here is what I'd received so far.

P0108 (MAP pressure circuit high) & P0123 (Throttle Position Sensor Circuit High)

I thought these may have been related to the repairs and the fact that I cranked the engine over to check compression when the intake and ignition was off the car. I was able to clear those by disconnecting the cam position sensor, running a PCM scan, clearing the codes, and then 108 and 123 did not come back. (I read this on the forum),

But then I received:

P0128 (Coolant Temp below normal) and P0440 (EVAP system), I thought 128 might have been due to the engine being a little low on coolant because of the water pump / radiator replacement and I noticed two wires going to the EVAP system were a little frayed. I added coolant and taped the wires, cleared the codes and they did not come back.

But then the next time I started the engine I received the following two codes:

P0031 (O2 heater control circuit low bank 1 sensor 1) and P0037 (O2 heater control circuit low bank 1 sensor 1)

I'm thinking my problem is probably not these individual issues, but possibly something with a ground or the PCM.

I really appreciate any advice. I am really stumped and it is getting frustrating. Every time I think I have this car fixed, something else pops up.

Thanks,

Jim