This is caused by your PCM being unable to adapt enough to correct a problem in the fuel/air mixture. This can be caused by several things, not necessarily in this order. Catalyst plugged Bad Powertrain Control Module Engine parts tolerance Fuel injector(s) stuck open or leaking MAP sensor O2 sensor (upstream) Fuel pressure regulator Wiring harness/connector problem
P0172 = System to rich (bank1). Year, make and engine would help us help you better.
P0172 System too Rich (Bank 1)
In my 98 Saturn SW2, P0172, system too rich, was caused by a bad engine coolant temp sensor. This is a common failure in these vehicles.It's cheap and easy to replace, and worth trying. When you take it out, if it's the original, it will be cracked. The new ones are metal. It takes a 13mm deep socket.
P0172 System too Rich (Bank 1)
Code P0172 means: System Too Rich
Fuel system running lean.
Trouble code P0172 means: System too rich (Bank 1)
Trouble code P0172 means: System too rich (Bank 1)
Trouble code P0172 means: System too rich (Bank 1)
Trouble code P0172 means: System Too Rich (Bank 1)
Trouble code P0172 means: System Too Rich (Bank 1)
Trouble code P0172 means: System Too Rich (Bank 1)