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This code was set in my Civic last week and I’m wondering where to start? My scan tool says “Rocker Arm Actuator System Stuck On Bank 1”.
I’m pretty meticulous with my car so it’s quite disappointing. A little of my research has pointed to gunk in the oil system but like I said, I’m pretty consistent with my oil changes and I use good quality oil and filters. I ran half a can of Seafoam in the crankcase oil for a few hours driving and then changed the oil. Didn’t make any difference. I had a good look at the wiring and connectors and I see nothing obvious.
Won’t rev past 3500 RPM and the cruise won’t set. Apart from replacing the Vtech oil control solenoid, what could I do?
Cheers!
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I’ve actually done a video on how this system works.
That said, as pointed out in the article above, most times it’s low oil or incorrect oil that causes VTEC problems.
Good luck and keep us posted.
So from reading about the V-tech system and watching some helpful Youtube clips the way I’m understanding this is:
At high RPM’s the ECM is supposed to command the Vtech system to engage. Power is sent to the rocker arm oil control valve solenoid which sends oil under pressure to the pins in the valve train, locking them together and changing the cam profile.
The oil pressure which is now present in the rocker arm oil control valve actuates the oil pressure switch (telling the ECM that the VTECH hydraulic actuating system is working correctly). The switch is normally closed to ground and the presence of oil pressure opens the switch. The ECM “sees” voltage (12V) rather than being connected to ground (0V) and all is well.
My car is throwing the P2647 VTEC Oil Pressure Switch Circuit High Voltage code at startup. If I clear the code, it returns immediately after start up. So, without doing any testing I’m thinking that at startup, the ECM should be seeing 0V at the oil pressure switch. The fact that it says high voltage makes me think that the switch is open……it should be closed at idle with no Vtech engaged. The ECM sees 12V when it is expecting 0V and throws the code.
Now, I’m assuming a little here but I want to think i’m on the right track and have a place to start. I’m thinking remove the oil pressure switch and clean it. I guess, conversely, the rocker arm control valve could be stuck on too at low RPMS…..therefore, oil pressure would be present at the switch. Would cause the same symptoms I believe.
There’s lots of voltage testing that can be done here so I will update with what I find. Damn thing is in a pretty crappy location though!
You’re a smart guy, and I agree with your next steps. You might consider checking the continuity of the switch with the engine off. There should be no continuity based on what you wrote. If there is continuity and it’s shorted internally, it will send a false signal back to the ECM as you suggested.
Here’s more info about electrical junk.
http://www.ericthecarguy.com/faq/solving-automotive-electrical-problems
Good luck and keep us posted.
Well I had a quick look this afternoon and I found a couple strange things….
First, my wiring diagram has two wires on the VTech oil pressure switch. When I looked at mine, I saw three. Yelow/red, black, and what appeared to be a green. I have no idea why there are three wires on this thing.
The other strange thing I noticed was on the VTech solenoid. I checked for voltage on the blk/wht wire with the key off and on….on both occasions, there was a steady 3.5 volts. Seems to me there should be none.
Well it appears my wiring diagram is wrong…..found this one this morning. It’s not a oil pressure switch, it’s a sensor. Appears to have a reference voltage. Not quite sure how to test this one.
Looking at the diagram I would say the wt/blk wire is the signal wire going back to the computer. I don’t know how it’s suppose to operate however. I don’t know if the signal is suppose to be there during operation or not.
That said I just looked this up and it appears the most common fix is replacing the VTEC solenoid. I often test these by adding power and attaching a ground. If memory serves it’s only one wire that goes to it. Just because it clicks that doesn’t mean that it’s good, but if it doesn’t click at all, then I would go ahead and replace it.
Keep us posted.
Hi Eric, thanks for the info….
I was out working at it today and unfortunately, I didn’t get anything definitive. I took the engine oil pressure sensor out and gave it a good cleaning. I re-installed, cleared the code and got the same code right away. I didn’t even start the car and the code popped up again.
So…thinking about the code description “rocker arm actuator stuck on”. How could the VTech actuating system be stuck on with no oil pressure? Don’t forget, the car’s not running and it’s setting the code again. Seems to me that the oil pressure sensor is “sensing” oil pressure even when the engine is off. Any residual pressure would have been relieved when I removed the sensor. Kinda makes you think it’s the sensor at fault. Of course, I could be wrong because maybe the ECU isn’t forgetting the code or something screwy like that.
I also disconnected the Vtech solenoid and manually energized it…..big solid clicks. That’s a good sign I suppose!
I called Honda and the engine oil pressure sensor is 170 bucks. The parts guy alerted me to the fact that the whole solenoid valve (oil press sensor, gasket and new filter included) is 170 bucks……might as well replace the whole thing.
Still though, I wish there was some way to figure out how that sensor works. I would love some proof before I blow 200 bucks.
By the way….if anyone runs into this and has to take that Vtech oil pressure sensor out, a 1-1/8″ deep socket will do it. Not sure what the Metric equivalent is and no doubt 1-1/8″ is not the correct one but it fits pretty snug. Lucky I had one from my days of working on aircraft. I had nothing near it in metric. Probably a 28mm or something.
So I’ve done a bit more research and this engine is interesting. Beginning with the 06′ Civic 1.8 I-Vtech Honda took a completely different approach to the Vtec system.
My car’s engine is running on the “hot cams” most of the time. It is only when you get out on the highway and hit cruising speeds that the rocker arm oil control valve is energized and the “economy lobes” of the cam are engaged. This is completely opposite to the designs of the past. I had no idea.
I guess my car is thinking (via the oil pressure sensor) that the economy lobes of the cam are engaged at all times rather than the traditional Vtec hot cams. I suppose this is why my car has an oil pressure sensor rather than a switch because of the various criteria that have to be met in order to engage the economy mode.
At startup, the economy mode of the cams is not supposed to be engaged (Vtech solenoid off). I believe my car somehow believes that oil pressure is present (faulty sensor, or wiring) and I’m getting the code. I would very much like to know if the oil pressure sensor operates like a potentiometer or maybe it generates a square wave and the ECU interprets the frequency. I guess I could test but it would be nice to have a scope!
Afternoon folks,
Before I condemn my 06 Civic Vtech oil pressure sensor I was wondering if someone can give me a known good measurement? I’m looking at the Vtech rocker arm oil control valve. Car sets the P2647 code immediately after key on (KOEO).
At rest, my Civic 1.8L has 5V on the yellow/black wire and 4.7V on the black/white. Green is ground. See attached wiring diagram.
I know it’s a big favor!
I just looked for info on your problem on All Data and it appears that there are specific tools and procedures to complete all the tests for your problem. I could post them for you but there are Honda tools and equipment involved.
Perhaps it would be better for you to have a professional diagnosis done so you don’t end up throwing parts at it and hope for the correct repair.
There is a strainer and filter. you may want to try and clean them.
Yeah those specific tools are just for testing if oil pressure is present when the Vtech rocker arm solenoid is engaged. Oil pressure present and have fault, replace sensor. This problem would either be one of three things: wiring (seems fine to me), rocker arm oil control solenoid (seems fine as well), or oil pressure sensor (likely fault).
I’m pretty sure the rocker arm oil control solenoid is functioning correctly as I manually engaged it and I heard a distinct RPM drop.
Part is 170 bucks…..I’m ok with this.
There’s no external strainer and filter on this engine. They’re built into the rocker arm oil control solenoid gasket.
Replaced the rocker arm oil control solenoid…….problem fixed. Runs great now. Wasn’t too bad of a job to do in the driveway.
FYI if anyone wants to know, the old oil pressure sensor read 4.7V on the signal wire with key on engine off and everything connected. New sensor read 0.7V with key on engine off. I guess that’s the fix, there’s something wrong with the sensor reporting high voltage at rest.
Thanks for all your help!
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