Camshaft Position Sensor Circuit Malfunction???!

[blade0015]

I got a check engine light, and I got the codes read and it got- P0340 Camshaft Position Sensor Circuit Malfunction. Now a couple months ago i was gettin a weird squeekin when the car would start sometimes but in the past 3 months nothing ever. Sounds perfect and the car runs amazing. (1998 Mercury Mountaineer 5.0). It doesnt say failure just malfunction?! Do i replace the sensor? unplug it? what do I do? If i have to replace sensor where is it? This site was a big help in the past so if u guys can help it'd be great. thanks

 

[ExplorerDMB]

A F-150 came in a long time ago with a similar issue. It was the CMP Sensor. It gets a little play in it and if left it can eventually damage the whole sensor and leave you stranded. Now, the sensor on the F-150 was near the front of the engine. It basically takes place of your distributor (which runs off your cam).

http://www.explorerforum.com/forums/showthread.php?t=155206

That should help

-Drew

 

[stang99x]

The camshaft position sensor reads where the cam is in turn, and relays that info to the computer to adjust fuel, air, and spark parameters. If that sensor goes out, you walk (and the same if you unplug it) WHat happens is the computer is trying to run the engine one way, but its actually running another. If you do experience a no start condition that occurs as the engine will turn and turn and turn but not start, you can repeatedly try to start for like 2 or 3 second intervals and sometimes that will get you one more start. But its more than worth it to get it replaced before you get a tow bill to boot

 

[Macgiobuin]

Found the problem.

I had the same problem with my '00 Merc mountaineer. P0340 kept coming up, even after replacing the cam sensor, wiring to the PCM, 2dry ign cables, sp plugs, head gaskets, swapped coils, geez... still came up every time I cleared it- it would run for the first trip, with no CEL turned on, then as soon as I started it, CEL is on and it is the P0340, again. Finally, I read on another forum that the problem may be the alternator. I just put a new one in about a month before the problems all started. How to diagnose: Charge up the battery. Clear out the codes. Run it until the P0340 shows. Bring it back home. Clear out the codes. Disconnect the alternator. Yes disconnect the alternator. Isolate the battery terminal at the alternator from any short circuits by wrapping it in elec tape. Take the car on the same trip. If the code does not set on, you found the problem. The voltage regulator is transmitting stray AC voltage that is being picked up by the cam sensor or the PCM and throwing the whole system off. Do the test in daylight with no loads on--no radio, no headlights, no blower.

"but did you have to replace the camshaft position sensor regardless or what. DO you have a part number for the voltage regulator on the alternator and where on the alt is it?"

I actually did replace the Camshaft position sensor. Later, I put the old one on a SNAP-ON MT3000A Counsellor oscilloscope, I saw that I did not ever have to replace it, but replace it I did. The problem may have been the diode plate in the alternator, or it may have been the voltage regulator. Replacing the whole thing (alternator) fixed it, so I never searched any further. The voltage regulator part number is #F6DY10316A. It is located on the back of the alternator and is plugged to the wiring harness. It is attached by 3 screws to the back of the alternator, and when you install it you have to hold the carbon brushes back by using a wire or paper clip as you install the rear cover back onto the alternator's rotor.

I didn't believe it was possible, but now I am a believer. -Mac

 

[Turdle]

This may help

http://www.explorerforum.com/forums/showthread.php?t=161590&highlight=chirp

 

[98moranger]

Cam Position Sensor

I own a 1998 Ford Ranger 4.0L with 110,000 miles that had the same problem. The check engine light cam on with the code for malfunction cam position sensor. The truck was running fine until the cold winter came. It was hard to start in the morning and barely had enough power to go up the street. I finally bought a replacement sensor, but it sat in on the self for awhile because of the weather and the stupid engineers decided to locate this sensor to back of the manifold and you need to be a contortionist to reach the darn thing.
I have a 3" body lift that helped me to reach the sensor. I found out that I was able to reach the sensor by removing the passenger's side plastic inner fender well housing, turning the wheel completing to the left and crawling under the truck. To remove the sensor top housing I had to loosen the hold down bolt and rotate the sensor so I could unplug the harness. Then remove the two small screws to the top part of the housing. I was shocked I removed the sensor housing to find the magnet in the top totally destroyed! I discovered that the lower section (cam shaft distributor) the part that passes through the top part of the sensor is also completely gone.
So I would advise you remove and examine the bottom and top part of the sensor. Oh by the way, it took me about 4 hours to get the stupid thing off. Good luck.

 

[muskegolake]

Alternator the cause

Mac was right... I had an alternator replaced in my 2000 Mountaineer 5.0L and immediately had the P0340 code pop. After seeing his post on here, I took it back to the shop and had them switch out the alternator and clear the codes. It has been fine ever since! THANKS MAC!

Muskegolake
Chicago, IL

 

[park7163@sympati]

I guess my reply is reduntant but I went through the problem after I replaced the alternator,I started having bad idle at cold start ,and of course the cursed cel came on with the cam sensor code .My mechanic diagnosed it he replaced the sensor with no improvement.I read this thread and when I went back to my mechanic with the print of it he did not believe me.I went back to the supplier and had the alternator checked and it was charging enough to keep the battery working but it did not produce enough for the proper function of the can sensor.I replaced the alternator and it cured the problem.Thanks guys for the help.
Regards
Jim

 

[park7163@sympati]

Just another question related to this thread.I have a 2000 5.0 L AWD and when the initial diagnosis was cam sensor I went to an aftermarket parts place and had them order a sensor and it came in as a three wire one as apposed to the two wire plug.My mechanic went to his parts place and they sent the same one.I went to Ford and they also listed a three wire one.The dealer then looked the part up with the VIN # and it listed the correct on(part number DU-81)

 

[fatalflaw]

broken sensor

The sensor can be bad or unpluged and you can still drive it the ecm will pick fixed values it will run like a turd but you can drive it for a long time that way years if you so desired that is my experience with 5.0 not sure about 4.0 im fixing my step fathers now while he is in hospital and the electrical connector has been broke for years now just thought that may help someone out that is tapped for cash and not sure

 

[Turdle]

The sensor can be bad or unpluged and you can still drive it the ecm will pick fixed values it will run like a turd but you can drive it for a long time that way years if you so desired that is my experience with 5.0 not sure about 4.0 im fixing my step fathers now while he is in hospital and the electrical connector has been broke for years now just thought that may help someone out that is tapped for cash and not sure

Bad advice, for several reasons.

 

[fatalflaw]

Bad advice, for several reasons.

That was not advice that is what he did and he drove it like that so long the check engine light doesnt even come on i suppose if it was a 6 cyl. It probably would not run i wouldnt recomend this i would put a sensor in it now who knows what the hell has been trashed due to him driving it he ended up giving me the explorer so i will soon find out. I was not trying to be an ass i was just relaying what i ran into this thing will no doubt be a challenge i just changed the premellenium oil the other day lol.