Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
First of all Hi everyone! (sorry if some the following text won't be fully correct, English ain't my main language).
So i own a 2001 Jeep Grand Cherokee (WJ) 4.7l v8. I've had the car for a couple of years now. Mainly use it in the winters period (lots of snow in northern parts of Sweden).
So the problem started a year ago and then got worse. It always starts right away if it's haven't been started for 15-20min or so. But if i shut it off and then tries to start it it will just crank and crank but not start and it throws P0340 - Camshaft Position Sensor Circuit Malfunction.
So i didn't even think twice before I ordered a new sensor, wasn't much money for a new one, I've read plenty about crank and cam sensor go bad in these cars so i assumed that was the problem.... I changed it and the fault was still there nothing had changed.
So i thought maybe i got a cheap malfunction sensor ( brand: meat and doria) a unknown brand for me here i Europe. Anyways i measured the sensor it had 5volts as it should and reacted to metal by dropping down to 0v when i tried with a wrench in front of it.
So at this moment i i thought maybe it had some play in the connector or a bad cable so i unplugged depinned the connector cleaned it and plugged in the sensor again. And the car fired right up.
Shut it off and tried again and the ever ending cranking was back and so was the P0340. Unplugged and plugged in the connector again and it started right away. I did this a few times and it worked every single time.
So i tested to lift the negative on the battery for a second and put it back, this work as good as unplugging the sensors (and is a lot easier) she starts every single time when doing either of these two thing and doesn't throw the cam code.
But from here I'm lost, i don't know what to check for anymore. Maybe the PCM? Do anyone of you guys have any idea of what to do now? Does a new PCM require coding to work in these cars or is it just a easy swap? Know a guy with a jeep just like mine might be one year difference in model but other than that same. Could maybe try his PCM?
It will be helpful to look at Scandata, while running and when cranking and not starting. There are several pids shining some light on ckp, cmp, sync status etc.
These cars may flag a crank sensor code when In reality the cam sensor is bad. ...and vice verse.
Do you have a chance to get a scope on the car?
An expert is someone who knows each time more on each time less, until he finally knows absolutely everything about absolutely nothing.
