Manager Forum

I have this mustang in here that now the customer is concerned with his p0340 code now that it is not overheating.

I have power and ground to the sensor, ohm tested the wire from the sensor to the pcm. all good. Replaced sensor, and code still comes right back. It fluctuates about 5.94V ac to 6.44v ac at an idle both old and new sensor. The sychronizer looked ok when the cam sensor was off. Any help is appreciated. I did go with an aftermarket sensor, and maybe that is my problem. I usually only go with oe, but none available today, so I am ordering an oe, as aftermarket didn't change anything.

Is it possible to have a bad pcm???????

What did the labscope pattern look like?

pcm is a possibility. generally, when a code trips right away it's an open circuit. at least that's what i find. was the synchronizer removed for any reason? even if the customer say's no i would look at the anchor bolt. if it's been out it may be out of whack causing this light. it seems we are getting deeper into issues that have been caused by the owner fixing their own car. what else did he do? in the past i've been led down a path where every time i talked to a customer another bit of information was added. some "shade tree mechanic" may have thought moving the synchronizer would increase power and that was the beginning of the issues.

I think there is a bulletin from Ford on this. Cam codes can set from electrical interference either from a bad alternator or the old style aluminum body DPFE sensors. Check those first before you condemn the PCM. Also, make sure the sensor/reluctor is installed correctly. Some of these are tricky to set up. You have/are using the tool for this?

First the waveform was a even up down from the 5.9v to the 6.4v. It has a nice up and down waveform, and if I rev it up it flatlines at about 6v. The sychronizer does not look like it has been moved. I am going to pull the cam sensor back off and verify sychronizer line up. I did not see any tsb about the reflash for this code??

I didnt see any tsb's either but they could of sliped through. If the reluctors ok and the new pattern is good then Id look at wiring or pcm.

Yes, that was the old variable reluctance sensor. Later they went to a Hall Effect style with a square wave output. Two things you can do to see if the reluctor is installed correctly. Do a power balance test with your scanner with #1 injector disconnected. If you come up with a weak cylinder on anything other than one, then your reluctor is way out. If it shows cylinder one, scope cam and crank together. The bigger gap on the crank sensor is 60 degrees BTDC so it should be ahead of the center of the cam signal by exactly 60 degrees.

I did try to do a cylinder balance test and it was all over the place, disconnected #1 inj, and it sometimes would see that and sometimes it would read other cylinders. I could feel the miss in it, but wouldn't read. I did verify the sychronizer is lined up right. Can the crank sensor cause this code, or anything else? I have ohm tested the wires all the way back to the pcm, and they are all good, the signal, power, and ground. The other thing that has now happened is the batter light is on, but the gauge is reading ok. I think I have gremlins in this thing, or the customer is not giving the full story. Mitchells test all show testing with the breakout box, which that I do not have. This is where sometimes having more that one source of info is helpfull. May have to think harder about getting that Identifix!

SOunds like an alternator issue maybe it has bad diodes id test it. Its all coming together. Keep it up.

Ok, got my Motorcraft cam sensor here finally, and installed it, guess what, so far so good!!! Another reason I usually only use oem parts. The battery light only did that for like 5 starts then is no longer coming on either. I was in the process of testing further into that and it started working. Electrical can be fun chasing yourself around in circles. Next time I will just wait till I can get the oem parts too, some of this hassle could have been avoided. Well now to see if I can talk him into the timing cover that is seeping, and water pump that has some staining that he said was from him changing the stat last year. Kock on wood it keeps working here!! I was sure I had done all the testing that I had done before on these fords for the cam sensor codes, just aftermarket parts bite you sometimes. OEM!!!!!!!! Thank you!!

Glad to hear it's fixed.

As far as OEM parts...you betcha. Just had a BMW 840 in here for a cam sensor code. WorldPac sensor wouldn't even run. Got a dealer one and voila! Is it me or are parts just getting crappier and crappier?

ricmorin wrote:Glad to hear it's fixed.

As far as OEM parts...you betcha. Just had a BMW 840 in here for a cam sensor code. WorldPac sensor wouldn't even run. Got a dealer one and voila! Is it me or are parts just getting crappier and crappier?

Its not just u. and oe some stuff is crappy also

i'm shocked to hear that the worldpac sensor wouldn't work. usually they are oem. i've had products from them that had obviously been installed prior and have sent then right back. i was at a seminar put on by car quest a month or so ago and they put on a pretty convincing pitch about how they have revamped their product coverage. i'm still a bit uncomfortable using them for sensors and particular modules but i'm starting to use them instead of waiting a day or two for worldpac or oem. i really compare them and am seeing increased quality. this is restricted to car quest only. my other suppliers still sell off shore crap that i would only use as a fishing weight. while on this subject i'll add that some of the oem is crap to. i've taken parts out of oem boxes and could have purchased better at auto zone, it's the sign of the times. this may mean nothing but in the past i've weighed replacement relays and found them to be less than the original. it may mean nothing but it makes me think..........

You just dont know what ur gonna get ever really. I got a coolant sensor from oreiley and it was oe? WTf who woulda ever guessed.

you never know and always assume. one timei replaced a battery in a car and after a week or so the car was brought back in with a starting issue. i spent hours trying to track down a draw or starter/alternator issue. i just assumed the battery was good. well it wasn't. from that point on i alway's diagnose like nothing had been done, and if the flow points to a sensor or item that has just been replaced that's what i go with. at least 75% of the time the replaced part is crapolla. within the last few years i'm seeing oem parts tanking. a new twist that we don't need. even when i purchase the top line product or the new option the fail point has risen from 3% to about 5 or 6. i also want to warn about reboxing. i've noticed that on occasion i've ordered a let's say bosch (example product only, not to reflect on the products quality) and when i take it out of the box it's in a "uncle Charlie close to specification" plactic pouch.

I agreeI always start from scratch especially on a come back. New parts are not always good parts.