P0339 - Intermittent Crank Sensor Error - Not What You Would Think

[OSTMIKE]

Last summer and into the fall OST began receiving phone calls from various shops around the US with technicians asking if we could assist them with resolving a p0339 CEL that was putting their customer cars in limp mode. We recommended replacing the crank sensor and all indicated that they had already done that. Several shops indicated that they had also replaced the wiring harness and eventually the PCM. I suggested trying an oscilloscope on the crank signal wire. I did not hear back from these shops and did not give it a second thought - until it happened to us!

Long story short we replaced the crank sensor, made our own crank sensor harness to the PCM, replaced the engine bay harness, replaced and reflashed the PCM. Nothing permanently resolved the issue.

The difficult part is once we made a change (like a new sensor) the problem went away. We actually dyno tuned the car before the incident popped up for the first time. This made it particularly difficult to diagnose. We even switched to tuning with HPTuners and that appeared to resolve the issue for almost a week but the issue returned. Using my Witech I could watch the crank signal and it was clean. On occasions I would see the crank signal deviate from a clean square wave and throw the p0339.

We examined the tone wheel the best we could through the crank sensor hole and all the teeth were intact.

I eventually called back the shops that had this issue previously and none of them had resolved the issue. I was looking for a common denominator. All of the cars had an aftermarket crankshaft. The aftermarket crankshaft in all the vehicles was from the same vendor. Thecrankshaft vendor purchased the tone wheels from the same supplier.

The resolution after too many hours of troubleshooting was to remove the engine, disassemble the bottom end, remove the crank and replace the aftermarket tone wheel.

Once the defective tone wheel was removed and examined closely (with a magnifying glass) what appeared to be a manufacturing defect became more visible in the gaps between the teeth.

A very costly fix.....

I just wanted to share in the event someone else is going through the same issue.

Update: I just wanted to add that this troubleshooting and eventual resolution would not have been possible without the perseverance of our shop manager and Lead Technician - Micah Doban. His willingness to work extra long hours and superior troubleshooting skills are a major asset to our shop and to the high performance auto community.

[BryGuy]

Are you at liberty to disclose the crankshaft vendor (in case others in this forum have their product installed) and has that supplier notified their tone wheel supplier?
I would think this would be a warranty issue against the crank supplier (or tone wheel supplier) for those people who have had the crank installed with the defective tone ring no?

Edit - now that I think about it, I would understand if you chose not to divulge the name of the crank supplier, except to those who might PM you because they have the same unsolvable issue.

[ChuckWagon]

That there is dedication to finding out the root cause of the problem! Beans applied I know many other places that would've shrugged and kept ineptly trying to resolve the problem.

Can you enlighten us to what the manufacturing flaw or defect was? Any way to post a picture?

[OSTMIKE]

That there is dedication to finding out the root cause of the problem! Beans applied I know many other places that would've shrugged and kept ineptly trying to resolve the problem.

Can you enlighten us to what the manufacturing flaw or defect was? Any way to post a picture?

I'll try to get a pic up but it will not be easy to tell. However, after looking over the tone wheel as a whole (outside finish, standard cuts etc.) it became apparent that the manufacturer of the wheel (not the crank manufacturer) did a really substandard job.

[OSTMIKE]

Here's a picture of the defective tone wheel. Take a look at the gaps between the teeth.

[charginscott]

That is dedication to the industry

[chargerdriven]

On 2015 models only or older?

[OSTMIKE]

This is not limited to 2015 models.

[ChuckWagon]

Here's a picture of the defective tone wheel. Take a look at the gaps between the teeth.

So...it appears as though these were milled with a dull endmill. Are we looking at cracks in some of the radii or "chatter" from somebody trying to use a one to one endmill? A part like this should be laser cut and the recast removed by media blasting or etching of some sort.

Am I close? (never seen a reluctor up close first hand before)

[Rev Scorpion]

I know this is an old thread... and I know its asking a lot...

But is there any chance you could PM me some more information on this or PM me so we can discuss it a little further?

I have an 07 Charger in my shop right now. Spun a couple rod bearings... ended up being rebuilt by a reputable performance shop that my shop works with.
After the rebuild the car wouldnt start - intermittent loss of the crank signal. You could get a signal for a second and then it would drop out.
Replaced the crank sensor (went with OE just to be safe) since I could see the drop in signal. Car started and ran fine. Able to install a basic tune and drive it the 10 miles or so to the dyno... but during that drive it would occasionally "buck" (no codes at that point though).
Unable to do a full tune though because of the drop out of the crank signal. Car driven back to me with the P0339.
Figured I might have gotten a bad sensor and I had another one on the shelf anyway, so put in another crank sensor. No change. Engine will start but is showing a crank sync fault.
Pulled starter and crank sensor again and tested all the wiring from ECM to sensor and all wires test good (power, ground. and load carrying ability)
Scope pattern looks winky though.

Its awfully coincidental that this started after the rebuild.
Plan to pull the sensor again tomorrow and run my scope in the hole so I can get an up close look at the tone wheel and check to see that its even on tight.

Any help you would be willing to provide would be greatly appreciated!

Trying to find something conclusive to give to the builder to verify my belief that its a defective tone ring. Plan to pull the crank sensor tomorrow (again)

[OSTMIKE]

Replace the current tone wheel in the rebuilt engine with the tone wheel from the engine that was in the car previously (engine that ran but had spun bearings).

[Rev Scorpion]

I expect that is what is going to have to happen, but I have to convince the builder that doing so will fix the issue... and that is going to be a hard sell as he is convinced its electrical.