Expert: Roland Finston - 6/21/2011

Question
I have a Chrysler 300 limited I was advised to get the P codes from the vehicle they are as follows
P2996 Post Catalytic system Fuel trim Bank one to lean
P0138 02 Sensor Circuit High voltage bank 1 sensor 2
p0133 02 Sensor slow to reposed bank 1 sensor 1

Can anyone tell me what these mean

Thanks

Answer
Hi Lee,
All the codes are related to the function or the interpretation of data related to the two oxygen sensors located on the exhaust system on the right (passenger side) of the vehicle.
Sensor 1 is mounted on the exhaust manifold ( in the middle) and sensor 2 is mounted just beyond the catalytic converter along the pipe on that same side. The 0133 says the sensor 1 is lazy in its response which may be due to an exhaust manifold leak/dirt-moisture-grease in the connector at the sensor/engine mechanical problem/ or contaminated fuel. The 0138 says that the voltage on the sensor's signal wire is too high to be real and suggests that there may be a short circuit between the 5V supply wire and the signal wire at sensor 2. These wires are fragile and so could be touching one another. So look for that possibility.
The 2996 doesn't appear in the manual but based upon the description this may well be an interpretation of what would be the case if the reading on the signal wire were correct instead of due to a short.
So the first thing to do would be to locate both sensors and inspect their 4 wires for damage/touching/faulty insulation. Then remove the plug and check for dirt, etc. Ideally you will locate the problem before having to check the continuity of the wires/short circuiting in harness between the plug and the powertrain controller of both sensors. The oxygen sensors have the same general appearance of spark plugs but with 4 wires attached to their tips. Be very careful not to damage the wires.
Roland
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