If you get amber check engine light and find you get engine code P1259. The number corresponds to: vtec malfunction. Check wiring and Vtec solenoid. I removed the assembly and checked the small screen which was clean. Ordered a replacment sensor Vtec oil pressure switch part number 37250PCXA02. Cost $65, and takes ten minutes to replace yourself.

Had to wait a few days for the switch to come in. Once installed Vtec works again. Was an infuriating experience because the codes were too vague. There are actually three codes that say Vtec malfunction.....

This happened when my car pass 110,000 miles, so it might be happening to others who have high mileage.

 

I received the same CEL code over the weekend, P1259. I decided to open up the car in 3rd gear and got to 4th gear around 8K and felt a massive loss of power (VTEC died on me). I checked under the hood after searching my CEL code P1259 and noticed that my Vtec oil pressure switch harness was dangling and had snapped off on the tip (plastic clip). Sucks balls.. Thanks to your thread, I was able to get the part number to order the replacment. I was afraid that I had to buy the whole Vtec assembly if I couldn't find the part number for the Vtec oil pressure switch. I was able to find a website that has the Vtec oil pressure switch for $45 dollars (http://www.hondapartseast.com/parts/...lpressure.html).

 

The pressure switch is not guaranteed to be the only cause for this DTC. There are several causes, the 1st one being low oil level.