P1274 INFINITI Possible Causes
- Faulty Air/Fuel Ratio (A/F) Sensor 1 Bank 1
- Air/Fuel Ratio (A/F) Sensor 1 Bank 1 Circuit Open or Shorted
- Air/Fuel Ratio (A/F) Sensor 1 Bank 1 Circuit Poor Electrical Connection
- Fuel Pressure
- Faulty Fuel Injector
- Faulty Mass Air Flow Meter
How is P1274 INFINITI Code Repaired?
Start by checking the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.
Technical Notes
If one or more sensors are replaced, the Engine Control Module (ECM) mixture ratio self-learning clear procedure must be performed.
When is the Code Detected?
The A/F signal calculated by the ECM from the A/F Sensor 1 signal is shifted to the rich side for a specified period.
Possible Symptoms
- Engine Light On (or Service Engine Soon Warning Light)
- Possible Rough Engine Idle
P1274 INFINITI Meaning
The Air/Fuel Ratio (A/F) sensor is a planar dual-cell limit current sensor. The sensor element of the A/F sensor combines a Nernst concentration cell (sensor cell) with an oxygen pump cell, which transports ions. It has a heating element within the element.
The sensor is capable of accurately measuring λ=1, but also in the lean and rich ranges. With its control electronics, the sensor outputs a clear, continuous signal across a wide λ range (0.7 < λ < air).
Exhaust gas components diffuse through the diffusion gap at the oxygen pump electrode and the Nernst concentration cell, where they are brought to thermodynamic equilibrium.
An electronic circuit controls the pump current through the oxygen pump cell so that the exhaust gas composition in the diffusion gap remains constant at λ=1. Therefore, the A/F sensor can indicate the air/fuel ratio through this pumping current. Additionally, a heating element is integrated into the sensor to ensure the required operating temperature of 700 to 800°C (1,292 to 1,472°F).
