[John Clark]

That code means different things for different year vehicles and different engines. For your vehicle P2647 means "VTEC System Stuck On." There is an oil pressure switch involved but it's the oil pressure switch for the VTEC system. This switch is on the rear cylinder head on the driver's side. It's usually either a problem with the rocker arm oil pressure sensor or the rocker arm oil control solenoid. You need to have a y-connector and an oil pressure gauge in order to properly diagnose whether it's the pressure sensor or the solenoid.

 

[John Clark]

The way the system works is the solenoid is commanded on and off by the PCM. When the rocker arm control solenoid is commanded off (during 6 cylinder mode) it sends engine oil pressure to the rocker arm oil pressure sensor. That's how the system knows the VTEC/VCM system is off. When the system goes into cylinder pause mode the solenoid is activated and the oil pressure to the rocker arm oil pressure sensor is removed. That's how it knows it's on.

Essentially, either the solenoid is not turning on or the solenoid is turning on but the pressure sensor is not seeing it.

 

[John Clark]

If you're still getting that P2647 code then that's what I'd chase first. If you don't have the tools to diagnose it then your options are replace parts (solenoid would be next) or take it in for proper diagnosis. The VSA light often comes on when that code comes on but there is a code stored for the VSA system too. If the trans were slipping out of gear it wouldn't trigger that code and you'd have other codes, most likely.

 

[John Clark]

Every Odyssey with VCM should have that installed, no question. It won't fix this problem, though.

 

[John Clark]

It doesn't really work that way but adding the Muzzler will prevent other problems.

You have checked your oil level, right? Low oil level or dirty oil can cause this problem, too.

 

[John Clark]

The VSA light comes on in conjunction with some engine DTC codes so it's not uncommon to also have a VSA light when you have other codes. The Muzzler will NOT affect the current code you have. You need to fix the root problem.

 

[John Clark]

In order to fix this you need to be able to measure oil pressure at the sensor and do wiring integrity testing between the solenoid, switch, and the PCM. A professional scan tool that can display the solenoid and switch data will also be necessary. This code has nothing to do with the oil pressure switch down by the filter. It's even possible your engine oil pressure is getting low since you say this happens after the vehicle is hot.

 

[John Clark]

Were you able to get it fixed, this just started happening to my 05 odyssey exl. I recently got an oil change at valvoline and 200 miles after the check engine came on but also the VSA and it rattled a lot. Once I turn off the car and turn it back on the VSA light turns off and the rattling stops, about 90 miles later the check engine light turns off and repeats140 miles later. With a code P2647. Any suggestions? The oil used was 5w20

Check your oil level.