Acura Repair Questions? Ask a Mechanic for Answers ASAP
Hello, I will try my best to help you with your concern.
It was probably a conscience that the adding of 91 octane caused the light to come on.
P0401 is a code for the egr pintle having insufficient lift. The rod in the egr doesn't move up or down enough and the ecm monitors the voltage signal and turns on the light as a result. The sh-awd light will come on because the traction control thinks there is a issue because it senses the slight hesitation in the motor.
the repair is to replace the egr valve and clear the ports of excess carbon. after that clearing the codes and you should be ok from there