Chrysler 300 P0394
Got a Chrysler 300 S that goes into LIMP mode and throws a P0394 code. Has a new cam sensor on that bank and new oil and filter from the dealer. Swapped the cam actuator solenoid to the other bank and the issue didn't follow. Found the issue only happens when the oil temp goes above 205 degrees so before that it drives perfectly fine with no issues. I can erase the code and then drive it down the road a bit then it will pop back into limp mode and throw that code and that code only. Scoped both intake cam signals and the crank signal at the computer and drove it and when the issue happens all 3 signals look good and don't drop out. Also monitored the vvt oil pressure pid and the pressure pid is good. Looked up the computers software and found it to be up to date. Any ideas what to look for next?
I had one 3.6l in a wrangler bad magnet on camshaft out of box give me that code replaced camshaft second time gone code wasn’t present until I put first camshaft in as I had no way to test magnet aside from indexing on camshaft
Do you know if those magnet wheels are interchangeable from bank to bank? Maybe I can swap them and see if the code follows.
Hi Zakk, I would perform a harness wiggle test and narrow down where a possible connection issue exists. Monitor the scope while focusing on the bank 2 cam sensors. Make sure to inspect for any signs of rodent damages. Mice love to hide in small dark places and chew on the harness insulation. At this point, I do not think the oil temp is a related issue.
I have inspected the entire wiring harness and had the cam signals running on a scope while driving and paused the capture right after it went into limp mode. Went back and couldn't see any issues with the signals. Both banks looked identical on the pico scope. The issue definitely starts when the engine has been running for a long time. I've driven it multiple times and it never does it cold…
Has there been any previous work done,, maybe try a cam/crank relearn if it's available.
Yes, I replaced the other banks cam sensor. It came in with 3 codes. 2 for the bank 1 cam sensor and the other is this code I'm dealing with. I found the bank 1 cam sensor flat lined and all other circuits were good. Replaced the bank 1 cam sensor and now the vehicle doesn't have a long crank time and the bank 1 cam sensor is working. I didn't perform a cam crank relearn but the issue I'm having…
I have had this identical fault on a 12 Durango. Same motor and probably same PCM. I did all the testing you have done, the signal would never drop out on scope. Timing was perfect along with VVT operation. A PCM fixed that vehicle. Maybe heat the PCM with a heat gun and see if fault will set in the bay?? Also P0394 (Sensor “B”) is the Exhaust cam on bank 2, not the intake cam. That may be why…
I can try the heat gun trick, thanks. Also the code description says Bank 2 sensor 2 and when you look up the sensor description it says on prodemand that Bank 2 sensor 2 is the intake cam.
I apologize Zach. You are correct on the cam positions.
These galley bolts will set any of the following DTC’s: P0390, P0394, P0365, P0349, P0345, P0344, P0340, P0369, and P06DD if they are loose or fallen out. If you remove the valve cover you can sneak a 13 ¼ swivel down to them and check for tightness. If it has fallen out they “usually” come to rest on the ledge the chain guide between the timing cover and you can sneak it out with a magnet.
So did they ever correct these loose gallery plugs on the 3.6 or still ignored today . Is there a Service Bulletin # ?
No there is no bulletin and yes they still loosen up to this day even on the second generation with variable valve lift. FCA did release a notice called a STAR case along time ago to check those plugs but nothing else in print. There is no torque spec for them either. 12 to 15 ft lbs is acceptable with a ¼" extension.
Even worse than it being a "secret" is that the "circuit" DTC doesn't have most people even considering an oiling issue. You nailed it again Chuck! Scroll down to his picture if you hadn't checked back on this one.
Yes, this is interesting because I have done a bunch of research on this code and this issue has never shown up. Maybe I can take out the vvt control solenoids on the front and fish an inspection camera down to see if I can tell if those bolts are loose. Without a TSB explaining this it's hard to sell valve cover removal just to check for loose bolts. Thanks
The offending one for this code should be the intake feed on the left cylinder head.
Hi Zakk, you have an interesting case, and it would be insightful to take a good look at the waveforms. The issue might not be easy to see with eyes only, so I would like to perform a specific set of experiments, and I will send you a tip of 2DNTs for your efforts. Picoscope: Ch.A: CKP, Ch.B: CMP B2S1, Ch.C: CMP B2S2, Ch.D: CMP B1S2, Timebase: 2s/div (total 20 seconds on the screen) Number…
ok I got the captures you asked for or at least I think I did. I was kinda confused about the triggering you wanted. It made it so it will only record one waveform screen. Let me know if that's correct. I also added the scan data off of my scan tool of all of the cam data pids it offered. (right at the end of the waveform where the cam degree flat lines is where it went into limp mode)
I just had this problem. 2014 Durango 3.6, P0394 after about 150 miles after your clear the light. Finally scoped both cam sensors, and can see the intake can on bank 2 is pulling a very weak signal to the pcm. Make sure those signals all look identical for the most part.
I have scoped all the cam and crank signals at the computer as the problem happens and nothing drops out and all look good. Or at least they do to me.
Thank you, Zakk, this is exactly the kind of waveforms I was hoping for, 2DNTs sent. I only took a quick look so far, other than more than usual ignition noise on the traces around the time the car went into the limp mode – but I don't know if it is real or just picked up by the scope leads, nothing really stands out.
Thanks for taking the time to help. I'm starting to think the PCM is falsely throwing this code. The fault description says the code will set when the pcm doesn't see the cam signal for 5 seconds or 3 crank revolutions. So I belive I would have seen that during the multiple times I've scoped these signals. I'm going to check a few more things on Monday and if everything looks good then it looks…
Wow thats a lot of time too fail before setting a fault. Maybe you could swap the 2 exhaust cam sensor signal pins at the PCM. That would only work if the exhaust cam signals overlap each other at all times including during phasing. Could be worth a shot.
This is interesting. I have not ran into this but i have seen a few case studies about the magnets on the cams shifting.
Yes but don't you think that would cause a hard fault and not an intermittent one?
I guess it would depend on how far out of phase it is.
Hi Zakk, Have you read theory of operations in All Data under the code flow chart information? These cam sensors are a dual read sensor for each bank. It has a full flow chart that needs to be followed to the end.
Yes, I have and gotten to the last step which says to replace the pcm but I'm not 100% on condemning the pcm just yet.
Hi Zack, I am not being a critic or negative, just verifying your diagnostic approach. There are often many that request assistance but overlook the service information or only skim over it.
I appreciate any help. I only use those diagnostic trees as a guide because more often then not the tests they recommend performing end up just wasting time more then anything. But I do always read through them just to make sure I'm not missing something simple.
So I want to give a huge shout out to Charles Burcham! I opened the valve covers and found the galley bolt for the intake that keeps throwing the code missing! I looked down into the timing cover and found it sitting on a ledge. Was able to get it out with a magnet. Reinstalled the bolt and torqued it to 15 ftlbs. Found the other 3 bolts loose! I could turn them by hand. Torqued all the bolts…