DTC 16556
NOTE: If the diagnostic trouble code "P0172/16556" is set, the oxygen sensor control has dropped below the learning value limit in the "lean" direction, but the Heated Oxygen Sensor (HO2S) still recognizes "mixture too rich".
NOTE: If the diagnostic trouble code "P0172/16556" is set, the oxygen sensor control has dropped below the learning value limit in the "lean" direction, but the Heated Oxygen Sensor (HO2S) still recognizes "mixture too rich".