2006 pontiac gxp , check engine light is on codes po431, 430 cam sensor circuit, runs fine clear codes and returns in 2 days !
Congratulations! You have discovered that clearing codes without diagnosing and repairing the problem that caused the code only results in a repeat repair! You now know more than half of the "mechanics" out there.
OK, on a more serious note: First we have to get the codes straight or get the car straight...I'm pretty sure it is the code that is not correct....Code P0431 and/or P0430 are not valid codes for a 2006 Pontiac Gran Prix GXP. Those are evaporative emissions system codes that do not apply to your car. However, since you mentioned "cam sensor circuit", I will assume at this point that you meant to say P0341 and P0340....BIG DIFFERENCE!
The next problem is that although they are very similar, the troubleshooting charts are different depending on whether your GXP is equipped with a 3.8L engine or a 5.7L engine. If you want help with a problem like this it is REALLY IMPORTANT that we know what we are working on. Otherwise, you may get some VERY GOOD information that does not apply to your vehicle and the "expert" will probably be thought of as "incompetent" for giving you bogus advise. Then comes the bad ratings, and no testimonials, etc. and it wasn't the expert's fault he didn't have the correct information to work with!
It's just not FAIR!!!
For either engine, Diagnostic Trouble Code (DTC) P0341 is not necessarily a "Circuit" problem. Although it may be) This code is usually caused by mechanical failures - See the list below.
CONDITIONS FOR SETTING THE CODE
1. The PCM detects the following every 2 engine revolutions:
. A. 36 medium resolution engine speed signals
. B. 6 low resolution engine speed signals
. C. More than 1 cam sensor signal (herein lies the problem - there should be only one)
2. The conditions in item #1 above are met for at least 4 consecutive seconds.
When the conditions above are met, the PCM sets a "Pending" code for the current drive cycle. On the second consecutive drive cycle that that the same conditions occur, the PCM will store a memory code and turn the Service Engine Soon or Check Engine light on. This explains why it takes a couple days for the light to come back on...It takes a minimum of 2 drive cycles to turn the light on. If it fails on this drive cycle, and not the next, the counter starts over. It could conceivably take weeks or even months for the thing to fail two times in a row if it is an intermittent problem.
If it is failing on a regular basis, the conditions (or causing symptoms) can be verified by using a lab scope and tracing the cam sensor signal and the medium or low resolution engine speed signal. Just count the pulses - if there is more than one cam sensor pulse for every 6 low resolution pulses or 36 medium resolution pulses, the problem has been verified. Now, to find the actual CAUSE so we can fix it.
The most common cause of this is miss-routed or bad ignition (spark plug) cables that are "spiking" the cam sensor circuit.
This code can also be caused by:
Camshaft reluctor ring damage
The cam sensor coming into contact with the reluctor ring
foreign material passing between the reluctor ring and the cam sensor.
Wear or damage to the timing chain, timing chan sprockets, or timing chain tensioner
Excessive camshaft end play
Now DTC P0340 is really the opposite problem.
If your car is setting both of these codes at the same time, you have a really erratic cam sensor signal that should be VERY easy to verify with a scope.
DTC P0340 sets under the same conditions except instead of having more than 1 cam sensor pulse, there are NONE.
This code is usually caused by the cam sensor itself, however it can also be caused by the circuits to the cam sensor. The integrity of the circuits should be verified before replacing te cam sensor for this code.
Apr 20, 2011 |
2006 Pontiac Grand Prix