The heated oxygen sensor is more likely to be installed in a modern car than the standard oxygen sensor. The sensor can reach its operating temperature faster because of the heating element. The PCM will store the P0155 code in memory and turn on the engine fault indicator to alert the driver.
Oxygen sensors measure the oxygen content of the air that enters and leaves the catalytic convertor. These sensors transmit data to the engine’s control module in order to measure the efficiency of catalytic converters. The PCM uses the information from the O2 sensor upstream (the sensor that is located before the catalytic convertor) to adjust the air-fuel ratio.
Sensors only work properly when they reach the ideal operating temperature. The PCM controls the heating circuits to help them reach their ideal temperature faster.
The O2 sensor is located before the catalytic convertor. Bank 2 indicates which side of the engine the 2nd cylinder is on.
The PCM tests the heating circuits regularly to ensure that the oxygen sensors are working at the right time. The P0155 code is set if the PCM detects a problem in the heating circuit for the oxygen sensor located in the second row of the engine (based on the coolant temperature).
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What are the causes of fault code P0155?
The cause of fault code P0155 can vary depending on your vehicle’s make and model. This fault code can appear for a variety of reasons.
- Faulty sensor row 2 (Oxygen sensor)
- Breakage or wear of the cables that lead to the oxygen sensor
- Sensor circuits with an open circuit or a short circuit
- Blowing fuse for oxygen sensor heater
- Faulty oxygen heater
- The engine coolant temperature sensor is not working properly
- Low Battery Voltage
- Hose disconnected from the module of exhaust gas recirculation system (EGR).
- Engine control module fault (low probability).
What are the symptoms of fault code P0155?
The fault code P0155 might not have any symptoms. The most common symptoms include:
- The engine fault light is illuminated
- Difficulty in starting the vehicle
- Fuel consumption increases
- Increased emissions values
- The engine may occasionally stall
- Black smoke and a rotten-egg smell coming from exhaust
How to Fix Fault Code P0155?
- This code can be set if the engine coolant sensor does not work properly.
- This sensor should therefore be checked.
- If all looks good, replace the oxygen sensor.
- If the code appears again after replacing the O2 Sensor, the PCM must be checked and replaced.
How serious is fault code P0155?
The fault code P0155 can be categorized as moderately serious. This fault code can cause certain driving issues and increase fuel consumption.
