QuestionQUESTION: P1931 code, change cam and crank sensor. Would not start with new sensor. Put old sensor baqck in and runs fine. Still have P1931 code.
ANSWER: I think you mean 1391 code. You may be have a 'stale' code. So try disconnecting the battery for a minute, then run it again and see if the code is still present. It could be still a weak sensor, or the sensor is good but was installed improperly.
Roland
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QUESTION: we tried three crank sensor and two cam sensor. code was cleard each time. With the new sensor the engin would start but not stay runing. Put old sensor back in and it start and run fine. Cleard code, and after three start, code 1931 is back with check eng light on.
ANSWER: Hi James,
What is the size (L) of the engine? Now are you telling me that the old sensor (or did you reinstall both old sensors?) don't work either? You said it ran fine with the "old sensor", so that is no longer true?
It may have to do with how you are installing them or their wiring. So answer my questions and I will then be able to tell you about installing them and checking the wiring. Do you have a volt-ohm meter?
I assume that you mean the code is 1391 rather than 1931.
Roland
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QUESTION: engine size is a V6 3.9L. Let start over, check engine came on. code 1391 defective CMP sensor. First change crank sensor, engine would start but not stay runing and ran ruff. So change cam sensor, samething engine would start, but not stay runing. well we throught we had bad sensor, so got OME parts, same thing happen. Put old sensor back in, engine start and runs fine, but still have check engine light with code 1391?1f4pg
AnswerHi James,
This code is based upon a comparison of the cam signal levels at two positions and if they disagree then the code is set. It very well might not produce a noticeable miss of the engine, as your have experienced.
There are several causes for a 1391 code:
open/shorted 8v supply circuit
open sensor ground
open/shorted signal wire
excessive clearance of cam sensor tip
excessive clearance of crank sensor tip
failed sensor
failed PCM
Loose sensor connectors
I don't have the trouble shoot specific for that engine but as best I can tell you will find the wires at the PCM as follows, so you can check those out (while shaking the harness):
8v supply pin 7 orange
cam sensor signal pin 44 tan/yellow
crank sensor signal pin 24 gray/black
common sensor ground pin 17 black/light blue
On the sensor clearance issue, did the new sensors have a paper spacer on their tips? If so that means you put the sensor in until the tip touches the metal surface inside the hole. And if reinstalling then use a new paper spacer. Otherwise, just insert sensor to it stop point.
Roland
