Code 2646 and no acceleration

Hello, it's a rocker arm oil pressure code - which usually happens because the valve train is found to be starved for engine oil. Check oil level and make sure you have enough in the engine before doing anything else. Of course, by this point, further damage to the component or even internal engine components may have occurred due to lack of frequent enough maintenance and oil starvation. This is all an educated guess from someone who sees this stuff all day long for the last 13 years at Honda dealerships - and could be in error, but it's a reasonable guess from where I sit. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops