Faulty O2 Sensor
O2 Sensor harness is open or shorted
O2 Sensor circuit poor electrical connection
Extreme rich or lean air/fuel ratio
Air leak in exhaust near O2 sensor
Engine Light ON (or Service Engine Soon Warning Light)
HO2S Transistion Time Ratio 21 is the generic description for the P1154 Acura code, but the manufacturer may have a different description for your model and year vehicle. Currently, we have no further information
about the P1154 Acura OBDII code.