P0134: O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1)

What Does The P0134 Code Mean?

This code refers to the front oxygen sensor on Bank 1. Basically the oxygen sensor is inactive. Here’s why:

The powertrain control module (PCM) provides a baseline voltage of about 450 mV on the oxygen sensor signal circuit. When cold, the PCM detects the the internal resistance of the sensor is high. As the sensor warms up the resistance is lowered and it starts producing voltage based on the oxygen content in the exhaust.

When the PCM determines that the time it took for the sensor to warm up is greater than one minute or that the voltage is inactive (not reading outside 391-491 mV it views the sensor as inactive or open and sets the P0134 code.

What Are The Symptoms Of The P0134 Code?

One or more of the following may occur:

• Check engine light illumination
• Poorly running/engine missing
• Blowing black smoke
• Poor fuel economy
• Dying, stuttering

What Are The Potential Causes Of The P0134 Code?

A code P0134 may mean that one or more of the following has happened:

• Bad O2 (oxygen) sensor
• Bad heater circuit in the O2 sensor
• Wiring or connector to the sensor frayed / broken
• Blown heater circuit fuse
• Holes in the exhaust system
• PCM failure

How Can You Fix The P0134 Code?

The most common fix is to replace the oxygen sensor. But that doesn’t rule out the possibility of:

• Rusted exhaust pipe
• Inspect wiring & connector(s) for problems
• Excessive amperage blowing heater fuse (still requires replacement of sensor but also replacement of blown fuse)
• Replace PCM (only as last resort after all other possibilities are covered.

Recommended Parts

Below are some recommended auto parts to help you address the trouble code affecting your vehicle and get it running smoothly again:

>>> O2 Sensor
>>> Exhaust Pipe
>>> WORKPRO 582-piece Crimp Terminals, Wire Connectors, Heat Shrink Tube, Electrical Repair Kit
>>> ECU

Note: During the purchasing process, please check carefully whether the part you want to buy fits your car!

Check This Video For Reference

Reference Sources

Diagnostic Trouble Code (DTC) Charts and Descriptions for P0134 – Pages 33-34.