First time using these forums instead of lurking, so I ask you bear with me if I'm out of format.

Anyway, the question I have is if I have to relearn my crankshaft position sensor if it's an OEM unit.

More specifically, my 09 accord LX has been acting up for about a month now on startup. I do basically all of my own maintenance and the only time I've paid a mechanic for anything was for the starter (since it's under the manifold and I had nowhere to obtain a gasket for if it broke (which it apparently did)). In any case, I've only ever used synthetic 5w-20 in the four years (bringing total mileage up to 84K) I've owned it but the problem seemed to get severe the moment I went to start if after adding about 6oz of marvel mystery oil. It didn't crank until after about 12 rotations over 3 or so seconds followed IMMEDIATELY by a warning on my OBD monitor of a code for P0339 "crankshaft position sensor circuit A intermittent" and the check engine light. Well, crap. I pulled the unit out, inspected the sensor, cleaned it up a bit even, made sure there were no metal bits or shavings anywhere, even changed the oil the next day just to get the MMO out of it just in case. It seemed to start a little more 'normally' until about a week later which is today. It's a bit hesitant to turn over. It still manages and does so without a code (no code pending either) but I'm still worried. I have a new CKP, a denso to be exact, which is the unit that came in the engine off the factory.

Key points here are...
-It seemed to act up on the day I put the marvel in, but also never quite started before 4 cranks to begin with, even after new spark plugs and endless fuel system cleaning. I've used MMO in the crank case for years with no issue.
-I haven't gotten the CE code since swapping out the oil, but it seems to have the same symptoms that lead up to the code in the first place.
-The engine has no issue idling, has never stalled, hasn't had an issue with power on demand in years, and the tachometer seems to work perfectly fine even on startup (which makes me question the CKP at all)
-It HAS has the started replaced, and on that note, has had the battery disconnected to charged several times in a blind hope that I just had a bad alternator or battery cell. Battery, alternator, and starter are all OK.

Again, I have a brand new sensor, but I'm worried I'll have to relearn it and I don't have the honda scan tool, AND that if the sensor isn't the issue I'll lose the $60 investment for said sensor as once I open the package I can't return it. Not tragic, but still a waste. I suppose I could pop the sensor in, test it, and if it fixes nothing just plug the old one back in and eat the monetary loss.

Any insight on if I'd need to relearn an OEM CKP?

 

1. Generally, a CKP pattern clear and learn procedure should be performed after CKP sensor replacement (OEM or aftermarket).

2. The P0339 is more likely due to the starter even though it has been replaced. Some aftermarket starter will cause that, with the slow starting, etc.

 

I was really hoping that wouldn't be the issue... I gotta call tomorrow and ask what starter the mechanic installed. With the manifold in the way I can barely see the housing, much less any branding or decals.

 

UPDATE
I don't have a solution, but i have done a few things that may narrow it down.
-Removed and inspected both camshaft sensors
-Check cabling to both cam sensors AND crankshaft sensor
-Ran a full intake fuel system cleaning as well as a bottle of injector/system cleaner through the tank

The issue still exists but the development that has exposed itself is that the engine only struggles to turn over when it's still hot. If I make a quick 5 minute stop at the grocery store on my way home from work, it'll crank 10+ times before turning over, if at all. If the car sits for 15 or so minutes, it'll turn over with relative ease. Overnight, there's no issue whatsoever. If the car is at ambient temperature, it turns 3 times before starting up with no problem. I did get P0339 on my past trip to the store, the car was only off for a few minutes before I tried to start it again. While that code does exist, I've read that issues starting up only when hot can be linked to things like the fuel pump relay or leaking injectors. The relay is in the cab fuse panel, so I doubt it's that. As for the injector, that's a big maybe. I don't think they've ever been replaced. I HAVE tried pressing the accelerator on startup when the engine is hot, it doesn't seem to make a difference.

So, the short of it.
Cold- No issue
Warm- No issue, still experimenting Possible issue, depending on length of trip
Hot- Almost guaranteed cranking issue + possible CE light

 

I gotta say, its really weird that it all the sudden started taking tons of turning over to start after adding marvel's mystery oil. Where did you add it? I'm assuming the oil/crankcase?
I'm REALLY tryin to think of the relativity between the two and its hurting my head lol.
I would perform the CKP Sensor pattern clear and learn procedure just to narrow down the problem.
It makes alot of sense that your problem has SOMETHING to do with the CKP sensor since you have a code for it and it is one of the sensor the ecu uses during startup.

 

I'm guessing the MMO was a coincidence as I've gathered a bit more experience with the issue.

It still occasionally has an issue turning over, ONLY after shutting it down and attempting to restart before it has been allowed to cool for 10 minutes or so. This is NOT an issue during cold starts. I'm beginning to think the injectors may have something to do with it. I'll have to pull them and have a looksee at the state of the atomizer. My arguments against that is the lack of smoke on restart and the CE light only indicating a fault with the CKP and the fact that the car runs basically without flaw (it seems to hang on 3rd gear longer than it used to, nothing accelerating doesn't solve). Applying the throttle a bit on startup seems to yield a positive result but I did have one instance where even flooring the throttle on crank didn't help at all.

After all the time and observation of the issue, I'm still at a loss. Maybe it is the starter. I've debated finding a place to see if there's a software update available for the ECU, so that's on the table. As for now, I make sure that if I need to stop anywhere that the car has a few minutes to cool off before restarting.

 

Have you had any luck fixing the issue?
I’m having very similar problem but nnever noticed a correlation with after short stop except this last time 2 days ago... i read about it some have you seen service bulletin 09-050 (basically a PGMFI update and crank pattern learning. I have an appointment at honda for that tomorrow, about $90. If that doesn’t work i’m thinking starter might be next? I haven’t owned it very long and don’t know if starter had been changed, but seems like a common problem even though it turns over fine but possibly not quite fast enough? 2008 accord, 4cyl, 228000 km’s on it, new battery, spark plugs.

 

Hi, I'm having the exact same issue with my 2010 Accord automatic. I just recently changed the starter and noticed shortly thereafter it was taking longer to crank when the engine was warm. Has anyone had any luck with figuring this out?
Thanks,
Mark

 

update, honda says PGM update had already been done, crank relearn did not fix anything...
then i pickup the car and no more CEL, starts and runs fine. Time will tell if it fixed it for good.

 

I had the starter replaced before this issue so it's entirely possible that my car simply doesn't recognize the output of my starter as proper operation (supposedly hondas don't like anything but denso starters) so it's possible that the aftermarket starter was the issue, but I doubt that and here's why.

The issue only existed when the car was warm. Starting in the morning was never an issue, starting after it had been driven and sitting was never an issue either, but quick stops (IE, at the gas station) it would have a problem turning over. I think my next step is going to be checking my spark plugs to make sure they're genuine NKG and my fuel injectors to see if they're leaking.

 

If it is a warm start problem, you might want to try replacing the ignition switch (electrical portion). That part is relatively inexpensive, and a quick and easy replacement.

 

Thanks for your experience, Mr. Lemons. I know a lot of people have been claiming the whole "Denso" starter thing, but here's the problem. I changed the starter myself a few weeks ago, and I discovered it is a Mitsuba starter. My vehicle had 60k when I had to change it, so what does that suggest about the quality here? I think you're right about the spark plugs/fuel injectors route. I don't think it's the starter either, even if it's an aftermarket one.

 

Yeah, having my doubts about the starter. Still having the issue, still only when the engine was recently shut down. I've been playing with the throttle on startup and that hasn't helped at all from what I can tell and I don't see any smoke after during/after startup so I don't think an injector is leaking. The plugs appear to be genuine NGKs and show no abnormal wear or soot so fuel/air ratio is good. I'm going to try what Tech8 suggested with the ignition switch and just swap it out, for $30 it's worth a shot. Gonna be a while but I'll post the results.

With any luck I can put this thing to rest for myself and anyone else that stumbles across here.

 

Did you happen to figure out the issue? I'm having the same issue. Replaced the starter worked great on the 1st start up then started throwing codes for everything so far I've replaced the cps, all plugs and coils, and also the fuel pump. Now it's throwing new codes for evap and damaged ECM smh I can't sink anymore money into this car! Really need help figuring it out

 

ALRIGHT, so after years I had to come back (hunt this place down) to post the solution to my problem in hopes that I could ease the pains of anyone else who has had this issue. It's been almost 5 years, wow...

Anywhom, the issue I got to know for a long while occurred AFTER having my starter replaced, go figure. The kicker is that it was ONLY an issue if trying to RESTART the car when warm; it would crank and crank and if it didn't start up the whole thing would turn over with the Check Engine light on and the VSA light on as well. The code would always read the same thing: "P0339 Crankshaft Position Sensor Circuit A Intermittent". P A N I C !

I figured since I knew how to avoid the problem (stop trying to crank, let it sit for a few seconds, try again) I would just ignore it since the car really didn't DRIVE any different... until recently. Upon starting, I would get this horrible grinding sound like the starter was still clipping the flywheel after turning over. No good. I finally pulled the trigger after several years of thinking about this and dealing with it and got another starter. Whatever the mechanic put in there was going to be replaced with a Mitsuba and it was going to be done by myself this time.

To make an exceptionally long story short, IT WAS THE STARTER this whole time!

Apparently, Hondas don't like aftermarket starters and the cheap PoS starter that was in there was a Carquest unit (gag!) and it was playing hell with the ECU on startup for whatever reason. The long crank, the error code, the grinding, it was all from junky aftermarket hardware. Mistuba is the OEM starter for Honda, NOT DENSO! (At least in the case of 8th gen accords) So a grand total of about maybe 10 bolts, 2 nuts, a few wire clips, an hour, and some elbow grease, the starter was in and oh my god, the difference in sound and performance was amazing. The OEM starter is exceptionally quick and smooth, taking half the time and making half the noise of the carquest junk. I really must emphasize that the entire job was done with needle nose pliers and a basic ratchet set (using a 10mm, 12mm, 14mm, and 16mm, the 14/16 for the starter itself), I kid you not. As daunting as it may seem with the job requiring the removal of the intake manifold, throttle body, and filter housing, it was super easy. The youtube guide I watched featured the guy installing a, you guessed it, carquest starter. Just ignore that bit...

As a recap
Issues:
-Starter was replaced, problems began
-Long crank but ONLY when warm or hot. No issue at all on long road trips for whatever reason.
-Check Engine (P0339) and VSA lights
-Loud crank, grinding noise sometimes

Solution:
-OEM Starter made by Mitsuba (remanufactured in my case)

So there we have it! Almost 5 years later and I hope I can put peoples minds at ease if you're experiencing the same issue. Cheers!

(If this forum alerts users, take this experience for future knowledge)
@Ashlap89 @mdharris11 @Accordian47 @tech8 @SebK

 

Man, thank you so much!
I having the exact same problem with the CarQuest junk. Identified the starter issue and came here to help. Glad that you're already fixed it for yourself and posted the solution for us too.
Appreciate!