I have a client who brought their vehicle by because the light was on and it wouldn't rev over so many rpm's. I pull up the code 2646 which was is: Rocker Arm Oil Pressure Switch (VTEC Oil Pressure Switch) Circuit Low Voltage. I was only able to glance at it being that they had to take off but I was wondering if anyone has had that same problem and if so, what was done to remedy it. I saw that under different solutions was simply going back with a factory oil filter and under other solutions, the VTEC oil pressure switch was replaced. My other question is, Where is it?