Trouble Code P0036: Heated Oxygen Sensor Control Circuit B1S2

Following a check engine light and OBD-II scan, you now know that you have diagnostic trouble code P0036. You are likely wondering: what does the code P0036 mean? Below is some useful information on this code and its symptoms, causes and solutions.

What Does the Code P0036 Mean?

The diagnostic trouble code P0036 is a generic powertrain code that may be set by any vehicle with an OBD-II system. It is related to the O2 sensors that evaluate the amount of oxygen in the exhaust fumes relative to the amount of oxygen outside the vehicle. This helps the engine computer maintain a proper fuel/air ratio.

These sensors are more effective when the air is hot. So, they have heaters attached to them. Code P0036 indicates that there is a problem with the circuit connected to the heater on sensor two in bank one. Bank one is the side of the engine that contains cylinder one. Sensor two is the O2 sensor mounted behind the catalytic converter. For references, sensor one is the sensor in front of the converter.

Some details of the bank one sensor two heater are vehicle specific. For example, it may use three or four wires. Two are typically connected to the powertrain control module/engine control module. The other wire(s) provide power to the heater circuit.

What Are the Symptoms of Code P0036?

Typically, the only way to notice a problem with bank one sensor two is the check engine light and a code scan. The OBD-II scanner error code P0036 problem may cause an issue with the fuel/air ration. However, the heater is only used when the engine is running but cold. So, it is very difficult to notice any symptoms.

What Are the Causes of Code P0036?

Trouble code P0036 is generally caused by an electrical problem with the relevant heater. These are some of the reasons the code may have been set:

  • There is an open or short circuit in the wiring to the O2 sensor heater.
  • The ground strap for the O2 sensor heater is corroded or damaged.
  • The O2 sensor or its heater is faulty.

In rare cases, the code may be set by a faulty PCM/ECM. However, this is typically not the reason for the trouble code and would likely cause other, unrelated symptoms.

How Do I Fix Trouble Code P0036?

It’s time to diagnose and fix the trouble code. Keep in mind that different manufacturers may have special instructions for troubleshooting this issue. Purchase a service manual for your make and model to ensure that you have vehicle-specific information.

Start the troubleshooting process with a visual inspection of the sensor and heater wiring. Look for any corrosion or damage. Repair or replace any faulty components.

After this, if you found and fixed an issue, capture the freeze frame data from the OBD-II system. Then, reset the codes and run the engine again. If the code does not return, the problem is likely fixed.

If there was no damage or the code returned, unplug the sensor and use a multimeter to measure the resistance of the heater circuit. You will need your vehicle’s service manual for this. If the resistance is non-existent or out of range, repair or replace the sensor then check to see if the code returns.

Back-probe the ground wire and check its resistance against that of a good ground. Do the same for the power supply wire, comparing it against the power supply for a working sensor.

If none of these steps produce a result, the issue may be with the ECM/PCM. Consider seeking the help of mechanic experienced with your vehicle before replacing the ECM/PCM as this can be expensive.

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