i have had this cel on since i had my exhaust or header installed and want to know what to do? the code is p01352 heater circuit bank1 sensor1. i have the buddy club header with no cat installed. i dont know if i need a angle defouler for this or not i know i do but i thought it was the second o2 sensor that was needed to use the defouler? i think it came on when i installed my exhaust so i think it might be the sensor that is gone bad but because i have no cat should the second sensor be on or is it the first? the only code i have is the p0135. i dont know. any help would be great.