P0036 - HEATER OXYGEN SENSOR CONTROL (HO2S) CIRCUIT (BANK 1, SENSOR 2)

Vehicles that use fuel injection are equipped with Oxygen Sensors (O2), which are located in the exhaust system, go ahead and behind the Catalytic Converter (TWC). Its objective is to determine the amount of oxygen, to adjust the fuel system and achieve in this way that the air / fuel ratio is adequate; namely, 14.7: 1.

It is worth mentioning that, the O2 sensors (Oxygen Sensor) have a circuit that heats the sensor, in order to shorten the feedback time. Depending on the model, the sensor can use 3 or 4 cables, of which 2 are used for sensor feedback to the PCM (Power Train Control Module). The other two remaining cables cause the heater to power the circuit. As for the earth, if the sensor is 3 cables, it is connected to earth through the exhaust system, but if it is 4 cables, it has a separate cable that provides the ground.

When the diagnostic code P0036 is established, it means that the Oxygen Sensor located after the TWC (Three Way Catalyst) in bank 1, experienced a fault in the circuit of the heating element.

• Check Engine light illumination.

When DTC code P0036 is set it means that one or more of the following has occurred:

• The heating element circuit of the Oxygen Sensor may be short.
• Oxygen Sensor heater circuit wires may be worn or corroded in connectors.
• The ground wire coming from the exhaust system may have corrosion.
• Defective O2 sensor.

To solve the problems of the P0036 OBDII fault code you must do the following:

• Make a visual inspection of all the cables that are related to the Oxygen Sensor, verify that none of these have wear or other damage. Also, that there is a good electrical connection, repair or change as necessary.
• Using a DVOM (Digital Volt-Ohm Meter) configured on the ohm scale, performs a resistance test of the heater circuit. For reference you should use a wiring diagram. In the circuit, there must be some resistance. In case the resistance is excessive or is above the limit, it is indicative that there is an open circuit in the heating element, therefore, the Oxygen Sensor changes.
• Check that there is good ground on the ground cable and its connector. Check the resistance.
• Change the Oxygen Sensor.