The description of fault code P0134 reads ‘Oxygen Sensor Circuit Activity not Detected’ (Bank 1, Sensor 1). This code is generated when the powertrain control module of your vehicle (PCM), located before the catalytic convert, fails to receive the signal from the oxygen sensor upstream. The cylinder number 1 is located on the right side of the engine. The oxygen sensor is located close to the engine, before the catalytic convertor. O2 sensors measure the amount of oxygen present in the exhaust. One O2 sensor is located upstream (before the catalytic convertor) and the other downstream (after the catalytic convertor). The downstream sensor is called’sensor 2’, while the upstream sensor has a name of’sensor 1’.
The PCM uses a signal from an upstream sensor for fuel control, and a signal from a downstream sensor to determine efficiency of the catalytic convertor.
All modern oxygen sensors must be heated. The PCM activates the heating element of these sensors when the engine first starts cold. This allows the sensor to reach its operating temperature quickly. Similar to glow plugs
The PCM will ignore the O2 sensor signal until the PCM has warmed up.
The PCM monitors how long it takes the oxygen sensor warm up. The module will consider the sensor faulty or opened if the process is longer than expected by the PCM and the oxygen sensor doesn’t respond. The module then illuminates the engine error light and stores the fault code P0134 into its memory.
Table of Contents
What are the possible causes of fault code P0134?
- Faulty o2 sensor
- Faulty faulty O2 heater circuit
- Broken or disconnected cables
- Loose connector connection and corrosion
- Heater circuit fuse blown
- Engine vacuum leaks
- Holes on the exhaust system
- Engine control module faulty
What are the symptoms of fault code P0134?
- Engine fault light illuminating
- Engine misfiring and/or stalling
- Hesitation during sudden acceleration and loss of engine power
- Idle speed fluctuation
- Rotten egg smell and black smoke from the exhaust
- Increased fuel consumption
- Increased emission values
How to Fix Fault Code P0134?
- It is necessary to reset the code and perform a road test. To see if a code is returned, the vehicle must be brought to its normal operating temperatures. You should correct any wear, corrosion, or loose connections. The code should then be cleared after any corrections and the test drive performed again.
- Some vehicles come with a fuse that controls the circuit for the oxygen sensor heater. It is possible, although not common, that the fuse has blown.
- Test the O2 sensor to ensure it receives the correct voltage from the PCM.
- If none of the above measures are successful, then it is time to replace the O2 sensor.
- Check the exhaust system if the code appears again after the sensor has been replaced. The O2 sensor can be affected by excessive rust or holes in the exhaust pipes.
- The control module may be faulty, and it will need to be replaced.
How Serious is Fault Code P0134?
The code P0134 will not stop the vehicle from starting, but it may cause the engine to lose power. Ignoring this fault for an extended period can damage the catalytic convertor. This fault code has the most important effect on fuel consumption.
