Hey guys,

My car just threw the P2646 code indicating my VTEC pressure switch was giving an issue. I have a service manual (page 11-287) so first thing I did was check and top off the oil. No luck.

As I don't have an HDS, I can't exactly follow the diagnostic directions exactly. My car is not cutting out over 2000 RPMs like most people when they get this issue and other than the light I notice no difference in the car.

Anyone have some diagnostic input before I spend the 60 bucks to replace the switch? Thanks in advance.

Steve

 

Did you rev it over 4000 rpm? When I had this I topped it off with oil and revved it over 4000 rpm the check engine light cleared itself

 

Most likely the Vtec oil pressure switch is faulty, but small possibility of faulty wiring or ECM.

It's not perfectly clear, but I believe the Vtec oil pressure switch is closed when oil pressure is high and open when oil pressure is low.

Suggest checking whether Vtec oil pressure switch is always open (engine off and running). Check w/ multimeter across connector pins w/ engine off and running. If open both ways, the switch is bad.

If not, either wiring fault or ECM fault. Check wiring, if good, then ECM is fault.

good luck

 

Thanks for the quick response.

raider,
I've put the car through its paces since so I don't think that will fix it.

Texas,
I'll give that a go tomorrow and keep keep my fingers crossed its shot.

Thanks for the help guys. I'll report back after.

 

So I finally got a chance to work on it and I'm having issues. As I said I have the service manual and have spent a lot of time looking over it scratching my head. I've also consulted many youtube videos so I know what I'm looking for.

For some reason, for the life of me I cannot find the whole assembly. I know exactly where it should be but its not there...

I'm talking about he assembly pictured on this link. I figured since I have the 3.0 it may be in a different location but cant find any mention of it in the manual.

VTEC Rocker Arm Oil Control Valve Removal/Installation (K20Z)

Any help would be greatly appreciated. Sorry if I am missing something very obvious!

 

You have an OEM shop manual and it doesn't identify location of Vtec oil pressure switch?

I would suspect you're looking in wrong section. It's in the engine section on 4-cyl engine. On 4-cyl, pressure switch is located on cylinder head end. Since it must measure pressure available to vtec mechanism, it must be close to camshaft ends.

The link is not for the oil pressure switch, but oil control valve.

good luck

 

Look on the front of the engine around where the PS pump is.

 

Ah, found my problem. I have a 6-cyl and I was using my OEM manual which only covers the 4. I found the V6 supplement online. Found the switch, it was open both ways. I'll head to the store and report back when I switch it out.

Thanks for all the help.