I am at my wits end with this 2.4 Vtec Engine. Last week the CEL came on and my code reader produced Error Code P2646 Rocker Arm Actuator A-Bank 1 Perf Stuck Off. After Googling several sites on the internet I ordered a brand new Honda Vtec Spool Valve Unit Part # 15810-RAA-A03. I replaced it and found the old unit to have a very clogged up filter screen. I also removed and replaced the VTC Filter Screen on the front of the engine by the serpentine belt tensioner. It was also clogged up pretty good. I cleaned the passage way good and assembled everything back to normal. I cleared the Error Code from the car with my Actron OBDII unit. Oil level in the engine is normal. My son took the car out this afternoon for a short drive and the darn CEL has come back on again. I do not know what more could be wrong. I change the oil faithfully every 5K miles using Valvoline MaxLife 5W-20 and I have always used a Fram Extra-Guard Oil Filter. I have owned the vehicle since it was new. I do not understand how the engine can build up so much crud to block those screens like it did.

Update as of Friday 20/28/20. Today I removed, cleaned and electrically tested the VTC Oil Control Valve Unit on the passenger side of the valve head. One of the three screens was fairly clogged up. Valve unit cleaned up good and the solenoid unit is functioning when voltage is applied to it. I put it back into the cylinder head and reconnected the electrical socket. I just completely drained all the engine oil and replaced it with Mobil 1, using a brand new Fram PH7317 Oil Filter. I reset the Error Code again and took it for a test drive. As soon as I hit 3000 RPM on the tach the CEL light came back on and the car starts to buck again under load. Can anyone help advise me?

One more thing: WHen the DTC P2646 is reading out, the Cruise Control with not set to a speed. The Cruise Control Light is on but the unit will not set and hold a speed on the highway.

 

Did you change the oil pressure switch with the spool. If so you need to check the wiring. Also the screen you cleaned near the belt did you clean the passage way out. Check the screen again to see if it got clogged back up

 

The new spool valve unit came with a brand new oil pressure switch incorporated on the unit. However, there is a oil pressure sending unit just below the Spool Valve Unit on the engine block just above the Oil Filter. I have not touched that, but you do have to unplug it's electrical connection to replace the Spool Valve Unit. I simply unplugged it and then plugged it back in when I was done. I did clean out the front Filter Screen passage with a nylon small brush and a soft cloth. The passage way itself was not really that dirty, just the screen. I guess I could take it off again and check it. Was wondering if a ECU Reset would help matters?

 

It doesn't hurt to do the reset. Either something is still clogged up or there is a wiring issue

 

How many miles do you have? Have you been using full synthetic?

 

I bought the car brand new in 2007. It now has 81,600 miles on it. At 75K miles I switched from regular Valvoline 5W-20 to Valvoline MaxLife Synthetic Blend 5W-20. The oil is changed every 4,500 to 5,000 Miles. Yesterday I began using Mobil 1 Full Synthetic High Mileage Oil 5W-20.

 

Can you talk me through a ECU Reset or is that what I am doing with my Actron 9180 Scan Tool each time I erase the P2646 Error Code?

 

No your just erasing the codes. Just remove the positive and negative cables and put them together for 10 mins (I usually connect them with some wire. Connect the cables back up and let the car idle until it get to operating temp. Then let it idle for 5 more mins. Then take the car out to relearn shift points.

Now I don't think resetting will do anything for you but like I said before it doesn't hurt.

 

I think beginning in 2003 it used non-volatile memory, so disconnecting the battery doesn't reset it. Has to be a scan-tool with a "reset" function.