Recently joined the forums here. I'm having some issues with my 2019 Bullitt. I'm getting the P0300 (random cylinder misfire) and P06B8 ( Internal Control Module Non-Volatile Random Access Memory (NVRAM) Error)

The P06B8 comes and goes as I've reset the KAM several times now. However, the P0300 is constant but doesn't trigger the check engine light until it's been quite awhile. It seems to misfire on cylinder 4 more than the rest, yes, all cylinders are getting a registered misfire according to my scan tool. If I'm parked and in neutral, and revving to 2-3k, it registers about the same on each cylinder. When moving, engine at low load, and vacuum above 15 in-Hg, it misfires mostly on cylinder 4.

I really don't know what to do from here, I took it to the dealer and they basically told me "everything checks fine and we've tried everything" but I'm not satisfied with that obviously, especially when I've only had the car for a month and have the Ford Gold warranty for another 5 years. I've diagnosed as much as I can before I shotgun parts. Dealer wants it back next week to dive deeper into the issue.

Does anyone have some insight for me to give the dealer? If I can fix it myself, I will but I feel this is going to be a bad PCM or it's going to be an expensive DIY fix because it'll just be shotgunning parts.

 

This Is The Best Ford Service Info I Could Find. Hope It Helps. These are Supposed To Be Interactive & I Can't Provide That & Also Some Will Refer To Ford Service Equpment But Maybe Something Will Be HelpFul! Darn Cars Are getting too Complex!

KC


PCM P0300 Random/Multiple Cylinder Misfire Detected Description

• This DTC sets when the misfire detection monitor detects an engine misfire in multiple cylinders or the PCM cannot identify which cylinder is misfiring.

Possible Causes

• Damaged camshaft position (CMP) sensor
• Low fuel (less than 1/8 tank)
• Stuck open exhaust gas recirculation (EGR) valve
• Restricted EGR passages
• Misfire monitor neutral profile correction has not been relearned since the last mechanical repair

Diagnostic Aids

• One or more EGR passages may be restricted.

PCM P06B8 Internal Control Module Non-Volatile Random Access Memory (NVRAM) Error Description

• This DTC sets when a concern with the ability of the PCM to correctly store permanent DTCs is present.

Possible Causes

• Low battery voltage
• Battery or charging system concern
• VPWR circuit intermittently short
• VPWR circuit intermittently open
• PWRGND circuit intermittently open
• Damaged run/start relay

Diagnostic Aids

• Check for other DTCs and diagnose those first. Check for aftermarket performance products. Check for an electrical or charging system concern. If an updated calibration is available, update the calibration to the latest level. If an updated calibration is not available, clear the DTCs and repeat the self-test. If this DTC is retrieved after a PCM reprogramming, turn the ignition OFF and allow the PCM to complete a normal power down sequence. If the DTC is retrieved again, install a new PCM. Refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM), Programming the VID Block for a Replacement PCM.

Refer to the Description, Possible Causes and Diagnostic Aids for the DTC.

 

Has Vehicle Had a Clutch Replacement Recently??

KC

 

it has not but I've relearned the crank sensor and still nothing

 

Ok, It's an Item That Gets Overlooked! I Was Trying To Find Where I Had Posted it Before But Will Put This in as an FYI for Others!

Also Added Misfire Detection Montor Info Sheet From FORD! See PDF!

https://www.google.com/search?client...tion+procedure




KC

 

For Anybody Chasing Electrical Gremlins This Vid Really Opened My Eyes To How One Little Wire Can Cause a Long Term Chase!

https://themustangsource.com/forums/...issues-551265/

KC

 

Did the misfire monitor reset too!

 

Time To Watch The One Wire Video! It's Crazy The Complex Systems These Cars Have and One Bad Connection Will Have You Chasing Your Tail!

Sometimes It's Blind Luck You Find The Issue. For Me Usually When I get To a Frustration Point I Just Back Away and I Wake up at 3:00 A.M. Have A Smoke on The Porch and it Pops in My Noodle An Idea To Check Something I Had Overlooked! Sorry We Don't Have a Lot of Posters Here Recently and it's The Same At Other Sites. Here it is Just a Lot of Guests Reading Our Old Stuff When We Were Knee Deep in The S-197 Gen 1 Cars!

Shoot Me A Vin By PM and I Can Check Warranty Service History on Car if You Like For a Clue To Something Done in The Past Which May Shed Some Light. That is Unless You Know Car History.

KC

 

I Sent History To Email & Found This TSB Was Done. Not Related But Interesting.

KC

Also Had 22/S37 Done.


Campaign/NHTSA#
22S37/22V382

Issue Date
2022-06-01
Description
The powertrain control module pcm may broadcast an unintended faulted signal which when received by modules controlling the reverse camera, reverse light, and driver assist features, may disable these functions.
Safety Risk
A rear view camera or reverse lamp that is disabled reduces the drivers view of what is behind the vehicle, increasing the risk of a crash. A disabled driver assist feature traction control, forward collision warning, blind spot warning, cross traffic indicator may increase the risk of a crash.
Remedy
Ford Motor Company has authorized your dealer to reprogram the power train control module software to the latest level free of charge parts and labor.
Find A Dealer

 

Sent You Another Email!

KC

 

Info to Come As Per Phone Call!

Good Talking To You!

KC

 

A Bit More Info!

KC

 

Update as of 10 Dec 2024 - Dealer has had the car for about 2 weeks now. They say their "mustang specialty mechanic" is working on it. Whether this is B.S. or not, not sure but they haven't given me a reason to doubt them yet. This dealer does sell top tier Mustang's and pick-up trucks so mine feels like its the bottom of the barrel there. They have nothing but Saleen's, Roush's, GT500/350 and any other high end one you can think of. There was 1 other "low end" mustang there and it was a 2024 Mustang GT Darkhorse.

Anyways, the mechanic called and asked me some questions the day after drop-off. I left a good note in the car on what I troubleshot, thought it was, and the criteria for getting the misfire to actually occur since its very specific, (not trying to step on the mechanics feet) so he can re-create the events without having to guess on what's going on. I didn't tell them this but I verified all wiring (multimeter and tested it could carry current) from the injectors and the spark plug coils was all good to go. Okay good - we know it isn't an ignition or fuel issue, assuming the parts are good (they 99% are, especially when its every cylinder). So what else is there? Is it an air issue? Also not likely as the fuel trims were all good. The Intake Runner Control Valves operated when commanded by my scan tool without error so thats out too. The service advisor calls me today (10 Dec 2024) and tells me the mechanic has tested the fuel and its good too, its at exactly 10% ethanol. (eww, ethanol). So the mechanic is now forwarding the issue to Ford Engineers before tearing into the motor (if needed). This afternoon (right now when posting this), the mechanic is supposed to be doing a compression check on all the cylinders to see if the rings are worn and its a blow-by issue. I sort-of checked the compression with my scan-tool, utilizing the built-in compression check function which yielded there were no issues.

Will update as I get notified. Can't believe this is going on and i really do think its a PCM issue at this point, which I expressed.

 

Lets Hope They Can Solve The Issue Before Christmas & You Can Have a Happy New Year Going Forward!

Kc

 

Update from 21 Dec 2024 - service advisor and technician working on the car are getting advise from a Ford Region Tech (Ford Engineer is what he mentioned they would be considered). The advisor and technician want to throw new plugs in it just to make sure as the technician said he had one other mustang, a 1000hp Shelby, that had a random misfire that was cured with new plugs even though they all looked and fired good. Obviously these are 2 completely different engine builds but I can see where they're coming from. He doesn't want to tear into the motor yet due to warranty reasons unless the Ford Engineer comes back and says to do it. I believe the service advisor and technician already know exactly what's wrong, he mentioned if spark plugs don't fix it, he'll be trying to get me a long block (woah! Big jump!) I think with that info, they know what's wrong but they need to jump through the warranty hoops to get it fixed for me. I don't think the service advisor or technician told the Engineer what they found because it was probably out of the scope of the preliminary diagnostics. More to come as I get updates.

 

Thanks For The Updates & Hang in There My Friend!

KC

 

thanks again for the updates, interested to learn what's going on here

 

10 Feb 2025 - Picked up car from dealer last week, service advisor told me the tech couldn't really drive it due to the weather but said the number of misfires (6) were within the scope of normal engine conditions per Ford. All the tech did was replace all the spark plugs, I really wish he borescoped it while in there but who am I? I have a borescope and thought about doing it but I think tearing into the car myself here at home this far in will be a bad idea. The total number of misfires my scanner was logging before the spark plugs were more compared to after the new plugs, so I guess the new plugs helped but didn't solve the issue. Now back to the "within normal running conditions" - number of allowed misfires, my case was 6 per the service advisor. He tried to assure me that because it's a mass produced engine, it isn't going to be perfect. Okay, I get that but still... All of the other vehicles I've had and worked on for family/friends, don't have ANY MISFIRES. He told me he'd love to tear into the engine but Ford warranty won't allow that until a solid case has been built to require that, which would ultimately probably lead to an engine replacement.

I drove the car home, logged all the misfires on my scanner and when I get home, sent a photo to the service advisor with the data. The overall number of misfires (total on all 8 cylinders) were less than before the plugs but I registered over 100 misfires within 30min of driving on the highway. The advisor calls me and talks through what we're going to do next, which is more than likely an injector on the suspected cylinder and then block replacement. I told him that when driving, its mainly the #4 with the highest and most frequent misfires, I highly doubt the other 7 cylinders are actually misfiring even though the data shows differently.

They're sending a guy today to pick up the car, drive it to the dealership where they're going to try one last thing, throw in a new injector on #4 (seems to be the highest/main misfiring cylinder). I doubt an injector is going to work, I may of already checked the wiring integrity for all injectors and then measured the resistance of the injectors. I did these checks quite awhile ago. (I like doing my own diag to see if these "techs" are actually diagers or just part swappers, also like helping build a solid report to give the tech on where to start)

Will report back on what they find after the injector swap. The service advisor is very cooperative and goes out of his way to help me now, especially after the initial encounter when I discovered the issue shortly after buying the car.

 

***Car fixed and picked up 22 Feb 2025***

Alright guys, sorry for the late update. Stupid busy with work lately. They came and picked the car up from my house on the day of my previous post (10 Feb 2025). I received a call from them on Fri, 14 Feb . A new service advisor informs me they will be putting a long block in the car due to a damaged cam gear and crankshaft. I asked some very technical questions but she wasnt too informed on what the cause was. No big deal, I'll ask when i pick it up. They finished the car 21 Feb, just a week later, which is INSANE to me they were able to pull the engine, have a new engine shipped and delivered, and then installed all within 5 business days. I picked it up 22 Feb and got the scoop on what happened.

This is exactly what the repair invoice says "Vehicle still registering misfires, Cyl 4 is the worst. Verified customer concern and found vehicle would still register misfires in mode 6. Ran self test and found p0300 and p0316. Removed timing cover and found crank gear broken, crank and crank key have damaged each other as well. Found new crank gear would not go on crank. Set pic and results to Ford. Replaced long block per ford. ..." So I guess the cam gear broke, starting wiggling around and basically wore the crankshaft keyway out to wear to where it was unable to accept a new key and gear. The timing had to of been off just enough that the car's variable valve timing could compensate for the "wiggling" but not enough at a very specific engine rpm/load. Can't believe this happened and thank goodness I got the extended warranty.

 

Wow!

That is One For The Books!

I Guess Persistence pays Off! I Would Think At Some Point Catastrophic Failure Would Have Happened Had You Not caught it!

Glad it is Ending Well And Now You Have a New Engine To Add Some Years To Cars Longevity!

Thanks For Keeping us in The Loop!

KC