QuestionQUESTION: Hi. My other half has had problems with a Chrysler 300 cr they register as po107 manifold absolute pressure/BAROsensor low input and also po471 exhaust pressure sensor range/performance. Please would you be able to tell me how he can fix these problems? Kind regards yours frauke :o)
ANSWER: Hi Frauke,
I believe that both of those sensors utilize a 5 volt wire to operate. So if one of those blue/white wires at either sensor is short circuited to metal ground that would take out the 5 volt supply to both. My guess is that because the back pressure sensor is located on the exhaust system where it is more accessible to damage that its blue/white wire has be shorted.
You didn't mention the year model, but it may be later than my most recent manual for the car which is '06. But putting the car on a lift would be the way to find the back pressure sensor somewhere along the exhaust system. It would have a 3-wire plug one of which would be violet/white. The map sensor is mounted on the engine intake manifold and would have a similar 3-wire plug, but it is less likely to have been damaged.
Please read the PS below and respond to it.
Thanks,
Roland
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QUESTION: Hi again. its a Chrysler 300 crd it starts up but won't rev past 1500 Rpm once the temp gauge reaches the first quarter mark he can turn the engine of and re start it and it runs as normal then but if he turns the engine of before the the temp gauge reaches the quarter mark it will not start till the engine completely cools down. Again kind regards frauke
AnswerHi Frauke,
I would think that is has to do with the voltage supply to those two sensors as they both share the same 5v supply wire and I don't believe there are other sensors that use that (other than for the air conditioning pressure sensor). I surmise the "d" means diesel engine which I don't have a manual for but nonetheless I would go with those codes and check out the wiring for the two sensors starting at their plugs and going back to where they enter a wiring harness to see if there is any wire damage along that pathway. If that seems alright, then check that there is 5V on the blue/white wires at both plugs. If there is, then I would suspect the manifold absolute pressure sensor has failed as that would be the one that might cause the symptom you described when it fails.
Thanks for the rating, nomination, and kind remarks.
Roland
