P0134 Code – O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1)

Meaning:

The P0134 triggers when the the PCM has perceived that first O2 sensor in bank 1 is inactive or open
When the PCM has perceived that first O2 sensor in bank 1 is inactive or open, P0134 happens

The PCM has perceived that first O2 sensor in bank 1 is inactive or open because it has not warmed up after more than 1 minute of the engine running.

Main Symptoms:

Possible Causes:

  • Faulty O2 sensor
  • Short, open or broken wire in O2 sensor circuit
  • Exhaust leak
  • Defective heater circuit in O2 sensor
  • Heater circuit has blown fuse
  • PCM is defective (least likely but not unlikely)

Diagnostic Steps:

  • Visually inspect all wiring to first O2 sensor (bank 1) for loose, open or short connections
  • Use a wiggle test to determine where the voltage drops out
  • Visually check for exhaust leaks or air inlet leaks

Read More: OBD2 Codes List: Meaning, Fixes, and Free Download