How to fix the P0036 Code: Meaning, Causes and Symptoms 2023

The P0036 code is a generic DTC (Diagnostic Trouble Code) that shows when there is a fault with your vehicle’s downstream oxygen sensor’s heater circuit.

If you’ve recently found the P0036 code on your scanner. Find out in this article what it means, what the causes are and how you manage the situation. Here is everything on the P0036 error code.

What Does P0036 Code Mean?

This diagnostic trouble code P0036 means “Heated Oxygen Sensor (HO2S) Heater Control Circuit.”

This code refers to the malfunctioning of the heating element found in the downstream oxygen sensor located behind the catalytic converter.

When your powertrain control module gets a potential threat with the bank 1 sensor 2 oxygen sensor heater control circuit. The downstream sensor is known as sensor 2, and it is located in front of the catalytic converter.

Bank 1 indicates the location of cylinder #1. This heated oxygen sensor is commonly used in modern vehicles to regulate the sensor to the optimum range.  This P0036 code comes in Bank 1 and 2 types.

What are the Causes of a P0036 Code?

An opening inside the circuit of the oxygen sensor, or even a fault found in the H2OS secondary sensor will normally cause the p0036 code. When there is an exhaustion in the system ground strap, it will become corroded and trigger the ECM system to set the code.

While other fault codes are usually generated by many additional symptoms, it is not usually the case with this code (DTC P0036).

In most cases, the quick appearance of a new shining check engine light is the only sign that proves something is wrong. There is little or no chance of any driveability problems presenting themselves.

This originates from the fact that the sensor 2, bank 1 oxygen sensor that is identified by this DTC P0036 is found downstream in the catalytic converter.

Although, this sensor itself is usually used for a little more than just determining the catalytic converter efficiency. The sensor plays no major role in the determination of the engine’s fuel trim values.   

There are several potential reasons for diagnostic trouble code P0036. It is therefore very important to understand and recognize the most likely of these root causes if you want to solve the P0036 DTC itself. 

These are several of the common causes of DTC P0036

  • Nonexistent or corroded exhaust ground
  • Faulty PCM/ECM
  • Open in the O2 sensor heater circuit
  • Open in wiring to the O2 sensor heater circuit

Is Code P0036 Serious?

The DTC code P0036 is usually said to be of moderate and minor severity. The Sensor 2, Bank 1 oxygen sensor also plays a little role in the determination of how a vehicle should run, thus this prevents few that are if any drive-ability-related symptoms.

This actually generated from the fact that the circuit of the heater within the sensor (which is referred to by P0036) runs for a little less than a few seconds after the vehicle startup.

A car’s Sensor 2, Bank 1 oxygen sensor is located downstream of their catalytic converter which exists for the provision of feedback regarding the catalytic converter efficiency.

This is slightly different from its upstream O2 sensor, which helps to provide valuable feedback which is used to determine the engine’s fuel trims for the respective bank.

However, the main cause of the P0036 trouble code is supposed to be diagnosed and repaired almost immediately to avoid further issues. This is most important in states where yearly emissions testing is required because the presence of this DTC P0036 will always lead to testing failure.

If you do not feel like or have enough time to handle such repairs by yourself then it is better to contact the services of auto centers immediately.

How to Diagnose a Code P0036 

The following steps assist in diagnosing the main cause of DTC P0036. You should be sure to meet with a factory-specific service for the specific vehicle, before trying to repair it yourself.

Step 1: Check for the presence of any additional DTCs

Before you start the diagnostic process, make sure to check for any additional diagnostic trouble codes that might be present with an OBD II scanner.

If any of this code is found, it should be remedied that is the problem should be solved before step 2 can be done.

Step 2: Perform a visual inspection

To begin this diagnostic process, then the affected vehicle’s Bank 1 should be thoroughly inspected also with the Sensor 2 oxygen sensor.

Look for signs of damage to either the sensor itself or the sensor’s wiring. Make sure all repairs necessary are done before taking the next steps.

Step 3: Check heater resistance

Use a digital multimeter to check for resistance across the heater circuit of the sensor. Model-specific wiring that is a diagram of this should be used when trying to determine which pins of the sensor to probe.

A good amount of resistance should be present in this circuit, while if this reads an “OL” it indicates a failed sensor. When you consult factory service literature, you will find the exact permissible resistance range needed for the vehicle’s oxygen sensor.

Step 4: Check for power/ground

After you unplug the affected O2 sensor, check if there is any presence of ground and power at each particular pin inside the corresponding pigtail.

Again, the model-specific wiring diagram should be used and the values are to be checked within a few seconds after the vehicle starts.

Step 5: Locate point ground/power loss

If after testing in step 4 and a loss of power was detected and ground to the detected sensor, the exact point must be pinpointed to know exactly where the loss occurred.

You can do this by backtracking the pin where every signal originates from the vehicle’s PCM/ECM.

If ground/power is found at the ECM, then a defective circuit wiring is the problem. Again, the non-existence of ground/power at the car’s PCM/ECM would make one suspect a faulty control module.

Final thoughts

A diagnostic P0036 code can be checked for about $114.99, this is mainly for the HO2S Circuit (Bank 1, Sensor 2). Although all repairs usually come with a 12-month, 12,000-mile warranty.

P0036 code is mainly diagnosed with the OBD-II scanner. Many problems associated with this code are usually with the wiring because of heat from the exhaust damaging other components.

When trying to diagnose a P0036 code, do not assume that the HO2S should be replaced before you check the connector and wiring closely.

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