P1272 Air Fuel Ratio Sensor 1 Bank 1 Circuit No Activity Detected

Definition: This code indicates that the air-fuel ratio sensor for bank 1, sensor 1 is not showing any activity or response. The Engine Control Module (ECM) has detected a lack of signal from this sensor, which can affect fuel mixture and engine performance.

p1272 – Air Fuel Ratio Sensor 1 Bank 1 Circuit No Activity Detected

Typical Severity: Moderate

Common Causes

p1272 – Air Fuel Ratio Sensor 1 Bank 1 Circuit No Activity Detected

Common causes of this OBD2 code include:

• Faulty air fuel ratio sensor
• Wiring or connector issues in the circuit
• Exhaust leaks near the sensor
• Engine running too rich or too lean

 

Common Misdiagnosis

OBD2 Code: P1272

Description: Air Fuel Ratio Sensor 1 Bank 1 Circuit No Activity Detected

Common Misdiagnosis: Replacing the air-fuel ratio sensor without checking for wiring issues or ECM/PCM faults.

 

Common Diagnostic Steps

OBD2 Code: P1272

Description: Air Fuel Ratio Sensor 1 Bank 1 Circuit No Activity Detected

• Check for any additional trouble codes that may be present and address those first.
• Inspect the air fuel ratio sensor wiring and connectors for damage or corrosion.
• Test the air fuel ratio sensor using a multimeter to ensure it is functioning properly.
• Verify that there is proper voltage supply to the sensor from the vehicle’s powertrain control module (PCM).
• Examine the exhaust system for leaks, as they can affect sensor readings.
• If applicable, update or reprogram the PCM with the latest software updates from the manufacturer.
• If all else fails, replace the air fuel ratio sensor with a new one and clear any stored codes.