is probably a $95 Bosch sensor (from
www.************************************************************. Part # 15182 Oxygen Sensor - OE Type Before Catalyst) passenger side of a US car nearest the engine though it can also be a wiring problem.
Any exhaust place can change it for you...charge should be about $50 as it takes 10 minutes max once the exhaust system has cooled down and you drive it onto the lift. Or an easy DIY if you can get under the car safely.
I'm having a friendly tire place swap one of mine (just because they have a lift) with that part next week. And the dealer is 35 miles away.
Don't know if that will fix the 507 code.
P0507 Idle speed too high can be caused by the throttle valve sticking or a leak in the air intake system per the DME docs.