Mopar throwing codes

[Ozonkiller]

I've been hanging around this site for years mostly searching for info on my 460 BBF and my Kawasaki ZX14 but this problem involves mama's little PT cruiser. (2.4 liter non turbo with 52,000 miles). Smartest bunch of sumbitches that I know...

A while back I started to develope a slight miss. I changed the plugs (which were fagged out) from the stock Champions to iridium NGK's. All I did was change the plugs and while I was under the hood, the tranny fluid. To access the plugs, I lifted the upper intake manifold, but I didn't unplug or disconnect a thing, except of course, the plug wires. I buttoned everthing back up and bada bing bada boom the car ran smooth again.

A week later I get a check engine light and the codes are P0032 "O2 sensor 1/1 heater circuit high" & P0038 "O2 sensor 1/2 heater circuit high"

I find it hard to believe that both O2 sensors failed at the same time. I checked to make sure that I didn't acidentally unplug something or leave a ground wire loose.

I have researched that a bad ground could be causing this. I haven't found anything even closely resembling this.

With my Auto X ray scanner hooked up O2 sensor 1/1 voltage bounces all over so fast that I can't really read it 0.??? to .7??? while the sensor 0/2 reads a steady voltage of .724 volts.

Could it be possible that one sensor is bad and is back feeding thru the ground to throw a code on the second one?

I don't want to just throw parts at it.

Any ideas?

Thanks for your help,

Tom

[MagnumTPI]

The readings you are getting from both sensors are normal.

Double check the heater circuits, There are basic resistance heaters built into each sensor to get them up to operating temp faster. These are independant of the actual sensor feedback circuits to the computer for engine management.

Try to find a circuit diagram and check the entire heater circuit. I don't think both sensors went bad at the same time and 1 bad sensor cannot make the other appear bad, but both sensors may be fed voltage and be grounded from the same point, and if the supply voltage or ground is bad it could affect both sensors.

What year?

[NSS426]

Not sure what year your PT is but after about 2002 the computer supplied the voltage for the O2 heaters, and a common problem with these codes was the computer itself. IATN is a good site to research automotive problems, free to join a basic level.

[underhead valve]

I know that on some cars that the computer compares the draw on the sensor heaters, if 1 draws more than the other ---code ,have had this problem when replacing sensors and using 2 different brands, each had a little different heater draw and although the sensor part worked until the sensors were matched for heater draw the light would not stay out.

Look inside the connectors, perhaps one is corroded some.

[Ozonkiller]

Sorry. It's a 2005.

I went under the hood yesterday and tugged and wiggled the harness that runs behind the engine. So far, no light

Maybe this gives me a clue as to where to look. Chafing or something.

If I find a smoking gun, I'll chime in.

Thanks for the input.

Tom

[MagnumTPI]

You may have already seen this but i posted it anyway, just in case you continue to have the problem:


P0032 – O2 Sensor 1/1 Heater Circuit High

Possible causes include:

O2 Sensor Heater Operation
O2 Heater Element
O2 Heater Ground Circuit Open
O2 Sensor
O2 Heater Control Shorted To Voltage
O2 Heater Control Circuit Open
PCM


P0038- O2 Sensor 1/2 Heater Circuit High

Possible causes include:

O2 Sensor Heater Operation
O2 Heater Element
O2 Heater Ground Circuit Open
O2 Sensor
O2 Heater Control Shorted To Voltage
O2 Heater Control Circuit Open
PCM



Autozone will let you look at a Haynes or Chilton manual free of charge in their stores, find the PCM pinouts/ fuse wiring diagrams and 02 sensor wiring if you still have trouble.