03 PT Cruiser Turbo CEL Issues

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#1
'03 PT Cruiser will run fine for a number of weeks then suddenly throw 4 or 5 codes and start running like crap.
Codes show all 4 Injectors and both O2 sensor heater circuit failures. Once in a while I also get a code for coolant temp below thermostat regulating temp. This can occur even if the vehicle has only been on for a few minutes and is clearly not warmed up. If I clear the codes it runs fine till the next event days or weeks later.

I have cleaned and tightened the harness grounds, checked the pins and sockets on the ECU connectors, and slightly bent the ECU pins on the contacts that are in common with all the listed sensors.

It has to be in the harness or the ECU. Both are very expensive to replace. A local dealer tech told me the ECU may just need re-flashed. Does that make sense?if the program was faulty I can't imagine it would work at all.

This weekend's plan is to pull the harness completely and remove all the loom covering to look for shorts or broken wires then re-wrap. Unless someone has a better suggestion.
 
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#2
posting the codes would help -sometimes there is confusion as to exact description...Also if someone runs a TSB check.

Things I would also ask- as they are electrical
remote starter?
Ign switch?
vehicle is STOCK?
 
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#3
I will post the codes when I can. They are currently not present.
Car is stock. Does not have remote start. Not sure what you mean by Ign switch?

Thank you for your reply.
 
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#4
knowing the codes will help - look for something in common - ASD, IGN sw,

... the ign switch- do you have any issues there- wiggle key sometimes to start etc.
... STOCK- was wondering about T'stat... often see a lower rated T'stat installed ... and those problematic chips etc.
 
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#5
Having it reflashed might help, but I found a tsb about a campaign lettter they sent out about water intrusion in the ECU...says they will replace it for free...might want to check and see if that has been done....if not it may be a free fix....Jim
 
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#7
Spent Saturday afternoon stripping all the tape from the harness junctions everywhere I could reach. Slid the mesh covering back to check the actual harness splice points and to look for damaged wires. I found no issues with the harness. I also pulled all the connectors and checked for corrosion but they all looked fine. Next I cleaned all the ground points an added an extra one. When I was done the car started easily and seemed to run smoother than I recalled. Drove it for an hour Saturday and another on Sunday and it ran great. O I was quite pleased thinking I had solved the issue but cleaning all the ground points. Sunday evening we headed out for a drive with the wife at the wheel. Didn't make it 10 feet and the CEL was back on but the car ran fine. When we got back it was showing P0032 and P0038 (heater circuits for both O2 senors). I cleared the codes and decided to use it for my 1/2 hour morning commute. 10 Minutes out and the light is back. Same codes. Cleared them when i got to work. Drive home same issue but now the car is missing and running rough. Pulled over to check and found same codes plus P0125 (low coolant temp). Cleared them but they came right back.

Friday I stopped at the dealer to see if they had any advice. They suggested I perform the wiring harness check I had planned and looked up open TSB's. They found the one mentioned above and one other. The posted one would not cover the ECU or harness unless severe corrosion was found. Otherwise they just clean the contacts. Mine looks great with no corrosion.
The second TSB is regarding an available update to the PCM code and recommends a reflash. It does not specify that it will address anything I am experiencing and they will charge $80.00 to flash it.
 
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#8
maybe try another approach -
work as separate issues.. o2 issue and ECT issue...
How are you reading codes- the scanner will report manu specific - ie P1xxx ? AND is capable of viewing so called live data?

Using the scanner what is the voltage that the PCM is seeing on the o2 that trips P0032/38 ?
What is the PCM seeing as ECT?
If you can post that...

OR do scanner cost vs Time vs replace cost analysis
At the o2 sensors - first check the o2 wiring for pinched, chaffed, shorted to power or grnd.. Replace if NOT oem or htr resistance does not ck to spec.

P0125 easier to just R&R T'stat than remove test and reinstall...

OEM parts.
 
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#10
Scanner does not display live data. May need to pay for a good diagnostic if I am ever going to sort it all out. I still believe it is wiring related but monitoring all the sensors might help zero in on the issue. At least is would point to shorted or open and ground or power issue.

The thermostat, temp sensor and both 02 sensors are recent. Temp sensor and t-stat are Autozone parts. O2's are OEM.
 

kev2

wrench
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#11
A SWAG - an intermittant elec - lets look at freeze frame data AND confirm the alternator is not failing .

remove neg battery cable @ 10 minutes... I want to clear up something