4.6L P0340

[05FireRed]

hi, thanks for the registration and the welcome. i have a 2005 explorer, 4.6l that's setting dtc's p0340 and p1336. checked the cmp output to the pcm, getting proper voltage, but dropped a little when reconnecting to pcm, so replaced sensor - same results. disconnected alternator, same results. i did hear some pretty loud rattling once in the engine on start up about the time the codes appeared. also idles rough, and fuel mileage dropped. as i understand the pcm uses the cmp to find compression stroke to fire injectors and coils, but don't see where it verifies cam timing. guess my question is; would a timing chain out of time set the p0340 code, or what other possibilities could anyone suggest? thanks...

 

[SyberTiger]

How many miles on the engine and have the timing chains ever been changed out?

 

[Number4]

The rattling would be indicative of a timing tensioner or guide failure. But it tends to be constant (at least at start up) once it presents itself.

You could remove the valve covers to see if there’s chain slack.

Otherwise, check for voltage drop across the wires themselves. The crank sensor supposedly can be the cause for the cam sensor code as well.

 

[boominXplorer]

Commonly a bad alternator will set the p0340 code on mod motors because of interference. It could be the timing chains but you should get a cam/crank correlation code if that was the case.