I've had this problem for about a year. The CEL will pop on and the engine will go into limp mode until I reset the ECU. During the month of May, the problem got worse. It was doing this 2 or 3 times per week instead of only in the morning when it was cold out. Instead of buying a new sensor, I actually cleaned it out. So far it seems to be working (knock on wood).

I removed the vtec oil pressure switch, shook all of the oil out, then took some brake cleaner with the little red straw (didn't have a can of carb cleaner) and shot it a few times inside of the sensor hole. Careful not to spray yourself in the eyes when it blows out of there. I can hear something inside that rattles around. I'm only guessing here, but that rattle might be part of the way it functions. If it sticks because of crud build up, I'd also guess it would cause bad readings. Just for added value, I removed the VTEC housing where the sensor and solenoid sit and I cleaned it out too. Careful not to mess up the gasket or the screen.

It has been a week so far and I have not had any more CELs for P2647.

I have 106K miles on the car and have exclusively used Mobil1 since the break in oil.

 

Update: week #2 and it has not popped up again. I say it's fixed !

No need to buy a new sensor when you can clean out the one you've got!

Just hit 107K earlier today.

 

Yep, it must be those non-OEM oil filters......................NOT!

 

Per Wikipedia...
The VTEC system provides the engine with multiple camshaft profiles optimized for both low and high RPM operations. In basic form, the single cam profile of a conventional engine is replaced with two profiles: one optimized for low-RPM stability and fuel efficiency, and the other designed to maximize high-RPM power output. The switching operation between the two cam lobes is controlled by the ECU which takes account of engine oil pressure, engine temperature, vehicle speed, engine speed and throttle position. Using these inputs, the ECU is programmed to switch from the low lift to the high lift cam lobes when the conditions mean that engine output will be improved. At the switch point a solenoid is actuated which allows oil pressure from a spool valve to operate a locking pin which binds the high RPM cam follower to the low RPM ones. From this point on, the valves open and close according to the high-lift profile, which opens the valve further and for a longer time. The switch-over point is variable, between a minimum and maximum point, and is determined by engine load. The switch-down back from high to low RPM cams is set to occur at a lower engine speed than the switch-up (representing a hysteresis cycle) to avoid a situation in which the engine is asked to operate continuously at or around the switch-over point.

 

my cel came on with the same code and i took i took the vtec solenoid out sprayed som carb cleaner in the little pin hole and put it back took the negative terminal off reset the code and it hasnt came back and ive been able to hit vtec again finally lol no need to buy a whole new solenoid its happend to a lot of the 08 fits at around 100,000 miles especially the 5speeds like mine

 

its a simple DIY fix. here is something i poste RE: my same issue
https://www.fitfreak.net/forums/1044618-post6.html

 

Another 2008 Fit with the bad Rocker Arm Oil Pressure Switch. I replaced with new from Bernardi and all's well again. I didn't try to clean the old part so I can't say which is better but this seems to be a common problem. Took about 10 minutes to do the swap.

 

I was able to solve my CEL issue with codes P647, P2649 and 0113 by replacing the gasket that has the screen in it. Only cost $3. I posted on the 1st gen board how my Honda Guru Fukushima friend told me about it.

I bought my 07 Fit Sport 5 speed new, now I have almost 200K miles and this is the first problem I've had besides regular maintenance.

Happy dance

But maybe it just hasn't gone bad yet. I'll let u know.

 

Hi - Recently the CEL came on in my 2007 Fit. I took it to Autozone and they came up with the P2647 code. The oil level is fine. I even changed the oil but it made no difference.

The car runs smooth up until you hit about 4K RPM. It is like it has a governor and will not let you go past the set limit. It is not intermittent. It will not go away.

After reading this thread and others it sounds like the best bet is to replace the Rocker Arm Oil Pressure Switch (37250-PNE-G01) and gasket? As pointed out it appears to be an issue that Honda knows about (Honda has issued a service bulletin #13-021 to address any of these rocker arm oil codes P2646, P2651, P2647, P2652 on the vehicles listed below.)

If any thoughts please let me know. Thanks much!!

 

I bought a Bosche code reader with software that connects to my iPhone with Bluetooth.

It resets codes fine. I got it on sale for 70 bucks, not as good a deal as some but it works good..

These days I think its a must to have a reset tool for any car, too many ways the dealer can screw you for a 5 minute job..

 

everyone taking their car to the dealer to fix the sensor....how much did they charge you? i only ask because the sensor sits ON TOP of the engine and can be reached with your fingers...takes 2 minutes to swap and i am not exaggerating.