04em2civic

So I just bought an 04 em2. It has 130k on it. When I bought it 2 weeks ago I found out it needed a head gasket. Just got that done yesterday and picked the car up today. Ran great then when I hit vtec a couple times a check engine light came on for p2646. Shop can't figure out anything with it. Looked into it and found most likely cause to be fault pressure switch. I have one coming. I did the test of checking for continuity at 3000rpm with the sensor unhooked and found continuity at 3000. From what I read that means faulty pressure switch. Is there any other way to narrow this down? We just did an oil change on the car because of the bad head gasket. Oil level is fine. Vtec engages fine for a couple tries then does this. I should also state that on the shops scan tool with the car running it says the switch is on. If you drive the car the switch stays on and when vtec engages the solenoid opens. If I read correctly the switch isn't suppose to stay on all the time correct?

MassCivic

Try pulling the solenoid off and cleaning it out, could be gummed up jamming the spring inside or the filter screen could be really clogged.

04em2civic

Just makes no sense as it was perfect (minus the head gasket) before I had the work done. Now it's not something got messed up

ezone

Remove the valve cover.
Look for this bolt missing:



This wasn't my pic..
VTEC actuating oil pressure was bleeding out through the open hole.

04em2civic

Read about that, told tech after he put valve cover back on. And they were getting ready to close so gonna make sure they check that tomorrow.

CD_Hokie

Hello! Were you able to fix the issue? I just had head gasket replacement done at the shop. Same error popped up. Didn't have this error prior to the gasket replacement. Any info you could share would be a great help.

Thanks!
CD

ezone

Remove your valve cover and check yours out, or show your mechanic this thread and pictures and have them recheck their work

CD_Hokie

one of the bolts was not properly tightened! That's what was causing the problem. Thanks for the information! You are awesome!