P1149 ACURA Possible Causes
- Faulty Air/Fuel Ratio Sensor 1
- Air/Fuel Ratio Sensor 1 harness is open or shorted
- Poor electrical connection in the Air/Fuel Ratio Sensor 1 circuit
How to Fix ACURA Code P1149?
Start by checking the “Possible Causes” listed above. Visually inspect the corresponding wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.
Possible Symptoms
- Engine Light On (or Service Engine Soon Warning Light)
P1149 ACURA Meaning
The Air/Fuel Ratio (A/F) Sensor 1 is installed in the exhaust system and detects the oxygen content in the exhaust gases. The A/F sensor sends the output voltage to the Engine Control Module (ECM) / Powertrain Control Module (PCM). A heating element for the sensor element is built into the A/F sensor (Sensor 1). It is activated and heats the sensor to stabilize and speed up the detection of oxygen content by controlling the current flowing through the heater. An increase in current stabilizes when the voltage applied to the element electrode reaches a certain range because the amount of oxygen that is routed through the diffusion layer is limited. The current amperage is proportional to the oxygen content in the exhaust gases, so the air/fuel ratio is detected by measuring the current amperage.
If the A/F sensor (Sensor 1) voltage is low, the air/fuel ratio is lean and the ECM/PCM uses A/F feedback control to issue a Rich command. If the A/F sensor (Sensor 1) voltage is high, the air/fuel ratio is rich and the ECM/PCM uses A/F feedback control to issue a Lean command.
If the element is not activated or if the voltage across the ECM/PCM is a set value or less for at least a defined period of time when power is drawn to the A/F sensor (Sensor 1) heater, a malfunction is detected and a DTC is stored.