Hey all. Day before yesterday, my kid's 2010 4.6 L GT started running rough and spit out a P0345 code. Replaced the camshaft timing sensor and it knocked for about three more seconds and then it appeared to "relearn" itself. Check engine light cleared itself. Yesterday, he was out running about and it started acting up again and threw the CEL again. I didn't have my code reader, but it seemed to be the same issue. I have read that it could also be a bad diode in the alternator. Can this be tested without removing it from the vehicle? I just would rather be sure before dumping another $300-$450 on a replacement alternator.

 

yeah just use an ohm meter. There should be video on youtube that shows you how to check an alternator diode.

 

Thanks. Will try that. Someone from another forum suggested that a dying battery could throw that code, too. Any knowledge about that?

 

For that code to set, the ecm needs to see that the speed of the camshaft changed from it is expecting. So if the battery is dead enough that the speed of the camshaft changes from what the ecm/crank sensor is expecting it to be, then a battery probably could.

A lot of times, instead of throwing a misfire code, it will throw that code.

In example, say we take a spark plug out of the engine and leave your coil hooked up so it doesn't set a p0301 misfire code. The speed of the engine is going to increase dramatically on that cylinder because there is no combustion process going on. The first code set, would be the P0345 because the misfire is changing the cam speed, causing the cam sensor reading to be different.

 

So I was getting a misfire code - one generic and one for Cyl 5. I figured it was just a symptom of the camshaft code, so I didn't post it (especially since the replacement of the camshaft sensor seemed to fix the issue). Does that increase the possibility that the battery could be at fault as opposed to the alternator? Or could it be either?

 

When you tell me you have a misfire on cylinder 5, I am going to look at that.

Being a 4.6 and number 5 misfire, I am going to look to make sure no coolant got down on the cylinder after a thermostat change. I see people do that a lot, then just leave the coolant in number 5 cylinder spark plug hole.

 

What you posted right there is what google and everyone I come into contact with thinks. They are wrong on a Ford though. The misfire causes the cam code.

 

There are some instances where it can be electrical interference or aftermarket sensors, but if you have a misfire You have to fix that.

 

Had the battery and alternator checked out. Both tested good. Battery dated 12/2024. All current codes: P0022, P0316 P0345. Generic misfire and two for cam sensor.

 

I don't see p0022 on 4.6s very often. My 2017 f150 , it was the number one searched for code on identifix. I never did figure it out before I got rid of it. I just kept driving it because it didn't do it very often.

You really need a scan tool that will see mode 6 data so you can watch the misfire counters. If it doesn't show up there, a power balance test will find it. But with the generic misfire code, it should show up with the misfire counters.