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2004 F150 5.4 Triton engine light on Need help Fast!

I have a 2004 F150 with Triton engine. Engine light has been coming on for about a month. At first, ran rough at stop lights. Codes read and reported cam position sensor. Replaced sensors (twice!). When light came on after first set of sensors replaced, truck was taken to dealer. Now runs smooth but light comes on again in 2 days. Replaced spark plugs (after finding tool to remove broken plugs - what a joy!). Light just came on again. Help! We need this truck to tow camper in 1 week.

What do the codes read NOW…??

Reading P00123, P0340 & P0345 when taken to dealer.
Ran rough at first stop after driving expressway (no light on), then next time driving light came on (no speeds over 35 mph and running smoothly) - code P0012 (cam position sensors have been replaced twice). This occurred on 5-7.
Plugs replaced yesterday (5-10).
Light on during 4th time running since plugs replaced, code P0022.
VCT solenoid? - if so, why wasn’t it replaced at dealer when P0012 listed it as a probable cause and cam position sensors had already been replaced once.
If VCT solenoid - ideas of $$ or how it could cause futher damage to engine?

Malfunctioning Diode In Generator ?

Did the dealer look at any Technical Service Bulletins (like TSB 06-19-12) ?
I wonder about one that mentions 04-05 F-150s and PO340 and PO345 and the 5.4L and generator diodes. They discuss testing the generator frequency (wave patterns).
It’s a long shot, but maybe somebody could have a look.


common sense answer, do you mean TSB 06-19-08? I doubt dealer even thought about any TSB. They said they switched the cam position sensors and the code went away. As far as I’m concerned, all they did was take my $$ for something I had already done!
My ? now is - If VCT solenoid - ideas of $$ or how it could cause futher damage to engine? We need to tow for 3 hrs next week and don’t want to break down or cause more damage.

A bad diode in the alternator will allow a lot of A/C ripple in your electrical system and ALL the electronics will go bonkers…Have the alternator checked by somebody before you spend any more money…

I appreciate the opinions offered, but don’t think it’s a diode in alternator. No trouble with anything electrical.
Only problem is rough idle at stop after high speeds. Codes say variable cam timing retarded.
Noticed I forgot to mention it’s a 5.4L SOHC (if it matters).

I’d Have Somebody Familiar With Ford And F-150s Take A Look At That TSB 06-19-12.

Are you on speaking terms with a knowledgeable Ford Service Manager ? Perhaps with a phone call or stopping by, he/she will pull it up, read it, and offer an opinion.

I did a double take when I pulled up an 04-05, 5.4L Ford F-150 bulletin that was for sensor codes (PO340 for example). I was very surprised when it took off talking about the generator diodes, but that’s why it’s a Service Bulletin.

Anyhow, if you know somebody that knows auto electrics and can access the bulletin, I’d have them look. Get an opinion. They may recommend testing the generator. It may go nowhere, but who knows ?


"Replaced sensors (twice!)"
PO340-Camshaft Sensor
Two Camshaft Sensors Replacing One “Bad” Camshaft Sensor ?
What Are The Chances Of That ?

I can’t find a whole TSB to dowload, but here’s a link to the description.