code P0340

[terry5357]

car is really jerky while cruising then CEL came on, read the code (P0340) according to the SCT it is cam position sensor and (ckt) in the definition. I replaced the cam position sensor. Called LT Motorsports and they are saying its the assembly that is on the valve cover. I am at a loss and don't want to take it to stealership and say "fix it". I went to parts store and they said it is the cam syncronizer (which is what on the valve cover, passenger side by the way). HELP!

 

[terry5357]

by the way I did use the search. if car wasn't running so shitty I'd go with the alt. Like I said its rreally jerky while cruising, surges and jerks while at a constant speed.

 

[3VPOWA]

It's probably your alternator on the way out. Search on here with that code and that's what comes up.

Also, that's the VCT Solenoid poking it's head out of the valve cover.

EDIT: Saw your new post. Have you removed the alternator and taken it in to be checked?

EDIT 2: Noticed you had cams. My car did the same exact thing when one of the bolts backed out on the cam cap. Had to remove the valve cover and retorque everything down. My code was P0012, though.

 

[tmcolegr]

alternator

 

[2kanchoo]

I had the EXACT same problem. It was the alternator. Some diodes go bad on it and it sends a faulty signal to the cam pos sensor. There is a TSB out on it.

 

[terry5357]

It's probably your alternator on the way out. Search on here with that code and that's what comes up.

Also, that's the VCT Solenoid poking it's head out of the valve cover.

EDIT: Saw your new post. Have you removed the alternator and taken it in to be checked?

EDIT 2: Noticed you had cams. My car did the same exact thing when one of the bolts backed out on the cam cap. Had to remove the valve cover and retorque everything down. My code was P0012, though.

NOOOOOO!!! please don't want to have to remove valvecover ever again. guess I will have the alt checked. stilldon't understand why car is running so shitty. Working in Shreveport and driving back and forth on most weekends. Sure would suck to get stranded.Guess I'll have to take a couple days off since I am home and start trouble shooting. Wouldn't be surprised at alt being bad. Car has 65k miles and UDP's since 20kmiles. Thanks for help guys. Also thanks for not flaming me (yet). lol

 

[terry5357]

If I disconnect the battery while the car is running and it dies does that mean the alt is no good?

 

[JeremyH]

If I disconnect the battery while the car is running and it dies does that mean the alt is no good?

No it will always die you just opened thee circuit now nothing has voltage.


Do you have a voltmeter?

If you still have the stock battery it will likely read 11-12volts car off and car on idling if the alternator is doing its job you will see 14-15 volts at the battery.

 

[2kanchoo]

The alternator can still charge the car perfectly fine. Mine did for 6+ months yet I still had the surging and running shltty problem. It's a seperate issue, dealing with specific diodes in the alternator. Take your car to the dealership and ask them to look up the tsb for the alternator relating to the cam pos sensor. Then get them to test it.

Also, I've got about 55k miles on my 2006gt and I'm on my third alternator. The first one died completely, the second has the diode malfunction issue, and now I'm on my third. They seem to be problematic. I don't know of any highly recommended aftermarket ones. I just got lucky that my 2nd one was barely within a year from purchase when the diodes crapped out so I got it replaced for free.

 

[tmcolegr]

A volt meter most likely will not tell you if the alternator is responsible for the P0340 code. As stated by TSB 06-19-12:

"Some 2005-2006 F-Super Duty and Expedition/Navigator vehicles built prior to 12/14/2005 and 2004-2005 F-150 vehicles, equipped with 5.4L 3V engine, and 2005-2006 Mustang GT vehicles, equipped with 4.6L 3V engine, may exhibit a diagnostic trouble code (DTC) P0340 and/or P0344; or 2006 Explorer 4dr/Mountaineer and 2007 Explorer Sport Trac vehicles equipped with a 4.6L 3V engine may exhibit a DTC P0345 and/or P0349. This may be due to a malfunctioning diode or open phase connection in the generator.

Perform a generator frequency test to diagnose cause of concern. Do not replace the generator unless a frequency test indicates a fault. This TSB provides step-by-step directions for performing a generator frequency test using the WDS oscilloscope function."

 

[terry5357]

The alternator can still charge the car perfectly fine. Mine did for 6+ months yet I still had the surging and running shltty problem. It's a seperate issue, dealing with specific diodes in the alternator. Take your car to the dealership and ask them to look up the tsb for the alternator relating to the cam pos sensor. Then get them to test it.

Also, I've got about 55k miles on my 2006gt and I'm on my third alternator. The first one died completely, the second has the diode malfunction issue, and now I'm on my third. They seem to be problematic. I don't know of any highly recommended aftermarket ones. I just got lucky that my 2nd one was barely within a year from purchase when the diodes crapped out so I got it replaced for free.

Thank you very much!!!!! done deal. This thread can be sealed and shut down.

 

[Lupo222]

i got both codes after having my hot rods installed. I have three trips from NC to Florida and about 6000 miles on it over the course of a year and the car runs fine and the alternator is fine as well. I just got used to the CEL being on and I scan it every couple weeks.

The CEL will tell you that you have a bad (insert emissions component) but it won't tell you when you have a rod thrown or a hole in your oil pan. The CEL is almost pointless IMO

 

[silverstangz]

alternator

listen to this post its the alt !! trust us had the SAME thing !!

 

[terry5357]

Once again the forum has come through for me. Picked up a new one this morning, did the R&R and so far all is right with the world again.

I want to toss in a bit of praise here. I asked myself "how in the hell does a guy get from a cam position sensor error, to the alt being bad?" I have read and said "THIS IS THE BEST FORUM ON THE NET" and once again its been proven. Thank you to everyone who put their $.02 in. Makes me proud to be a member, EVERY time I get in a bind I can count on someone on the forum having a plan for a fix and it usually works out. Everyone have a great day, time to get back to Shreveport and get back to work.

 

[isthatguy]

its your alternator, same thing just happened to me, car would "buck" and feel like its lost power at cruising speeds. just replaced the alternator and everything went away, I had the same CEL code

 

[terry5357]

I know........lol. still wiping sweat off my face from replacing the alt..

 

[isthatguy]

I know........lol. still wiping sweat off my face from replacing the alt..

oh I bet, glad I got mine changed under warranty.. nothin beats free!

 

[RyNo]

This problem is a problem. Only mine wont fix lol

 

[sprchrgd s197]

I know........lol. still wiping sweat off my face from replacing the alt..

If you just replaced it with a stock alternator it's going to go out again. Trust me!!!!! Just buy the one from PA Performance and you'll be good forever. I went through 3 or 4 stock ones maybe 5 before I found out about the upgrade PA Performance has.

 

[scramblr]

If you just replaced it with a stock alternator it's going to go out again. Trust me!!!!! Just buy the one from PA Performance and you'll be good forever. I went through 3 or 4 stock ones maybe 5 before I found out about the upgrade PA Performance has.

^This. I went through 2 stock ones and then went with a PA Performance 3 years ago. Zero issues.