QuestionQUESTION: I have a chrysler 300 M 2000 and it's chrc light came on so we read the code for it manfactoer control ingnition system or misfire P1391 does anyone know what that can mean?
ANSWER: Hi Tina,
It says that one signal or the other (there are two signals) that come from an electronic sensor is disappearing momentarily at least 20 times in trip, during two consecutive trips. It suggests that either the sensor or its wiring or the engine part that the sensor observes is in some way faultly. It suggests that the wires to the sensor, or the part, or the sensor itself could be faulty and might be identified by visual inspection or testing with an electronic test device. The sensors are needed to time the sparking of the spark plugs and the injection of fuel.
In and of itself it is not of great concern until the signal it totally lost, in which case the engine will not run. So to me it would mean to be aware that this is happening and if the engine becomes notably losing its power or momentarily jerking that you need to find out which signal is missing and why because it may soon stop running.
I suspect one of the two sensors is beginning to fail. When it does so a code for which sensor will then be set and so the sensor would be replaced at that time. For now, if you have some experience in finding the sensors or you have a friend who does then simply checking that the wires are not damaged would be reasonable. Let me know which engine size size you have and I can describe where to find the sensors.
Roland
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QUESTION: Thank you for your response the engine V6 3.5 and do you think there is another tool I may need? someone suggest it may be an ignition module does this sound in the right direction or not?
AnswerHi Tina,
I doubt it is the "ignition module" whatever that is unless they meant the engine control module which is a complex and expensive part that does receive the signals from the sensors but also does many other things. No, I would keep my eye on the ball, e.g. the code, which is talking about the sensors. The cam shaft sensor is on the front left side of the engine mounted on the front timing case cover. The crank shaft sensor is at the rear of the engine on the right side, at the seam between the engine and the transmission. If you wanted to test it you would need a volt meter. But if it is intermittent at this time you probably won't find it that way, but rather with an expensive shop oscilloscope. You can wait until you notice it in the performance of the engine, then get another code readout, and that will tell you which sensor needs attention/replacement.
Roland
