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Toyota Repair/Iintermittent Rough Running 2004 Camry



2004 Toyota Camry LE
Inline 4
Automatic Transmission
225,000 km


Usually (about 95 percent of the time) the engine runs “perfectly”.
Occasionally, after being switched off for fifteen minutes or so,
it will start easily but will run very rough.
It tends to “chug” and will not make full power.
This condition lasts until the engine is shut down for a while.
The next time it is started, (typically the next day) the engine appears to run properly.

When the engine appears to be running properly, the MIL is ON.
When the engine is running rough, the MIL is OFF.
This appears to be opposite to what conventional wisdom would expect.
OBD II Codes:

The system has been scanned many times.
It always shows a P0032 code (O2 Heater Control Circuit) and nothing else.


The local “all makes” mechanic has attempted to find the problem several times.
He has run many voltage and continuity checks on the O2 sensor heater circuit.
He is convinced that there is not a problem in the sensor wiring.
In desperation, the O2 sensor was replaced ……… but the problem persists.
Spark plugs were replaced with no obvious change in performance.

Next Move:

The mechanic believes that he has eliminated every possible cause except the PCU.
There is no evidence of PCU mechanical damage or water  infiltration.
There are no OBD II codes that would indicate a PCU malfunction.
Replacing the PCU can be an expensive proposition with a significant risk of causing additional problems.

Any comments or suggestions would be appreciated.

Hello, the code is for the air/fuel ratio sensor located in the exhaust manifold, this is a very common code and normally replacing it solves this problem, I would recommend replacing it with a sensor from the Toyota parts department, your mechanic most likely used an aftermarket sensor, the code is specific for the sensor heating circuit, the computer either does not supply heating current or the wiring is defective, the sensor is bad and last, the computer is bad. Those are the only options. MAKE SURE TO GET THE CORRECT SENSOR, there are differences:
Is it a California certified emission car or 49state certified?
Is it a PZEV (partial zero emission vehicle)?
Check the label under the hood, for certification.
The NON pzev engine has a heat shield on the exhaust manifold, the pzev engine has no heat shield and the sensor is mounted on top of the manifold.

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I have more than 28 years experience as toyota technician, I will be able to answer most questions related to the Toyota product line up to the present year models,I am located in the US but welcome questions from other regions of the world. When asking a question please provide specific information: year,model, engine,transmission information. Provide as much information as possible including a brief repair history if possible. I have been a volunteer here for more ten years an have answered over 16,000 questions helping Toyota owners with their problems and save thousands of dollars without any compensation, some of my answers are published on many other websites including google and various automotive forums. DONATIONS ARE VERY MUCH APPRECIATED, IF YOU HAVE RECIEVED HELPFUL INFORMATION PLEASE MAKE A DONATION. AS OF TODAY (JULY 22, 2014) ALL REQUESTED GRAPHICS, ILLUSTRATIONS, DIAGRAMS, PHOTOS, WILL REQUIRE THE MINUMUM DONATION UP FRONT.


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