Modern cars have several features that cars built 30 or more years ago could only imagine. One of those functions is the control of emission gasses. There is a whole subsystem in the car which is the only goal to minimize the release of dangerous emissions. But, since it is a complex system, it can go awry. One of the most common issues with this system is a P0036 code.
When you hook up the car to the scan tool and get a P0036 error code, it is followed by “Heater Oxygen Sensor Control Circuit (Bank 1, Sensor 2)”. That means that the heater element inside the oxygen sensor is not heating the sensor fast enough. Bank 1 refers to the oxygen sensor that is located after the catalytic converter. The sensor 2 is considered a sensor downstream from the catalytic converter.
Oxygen sensors are there to monitor the level of oxygen in the exhaust gases. They play a major role in lowering the bad emission. This error code won’t result in performance issues, but your car will fail the emission test. To understand how the emission control system works, and how to fix this code, stay with us.
What Does the P0036 Code Actually Mean?
The P0036 code points to a problem with the oxygen sensor or its heated circuit element. The O2 sensor measures the level of oxygen in the exhaust, while the heated element heats up, and keeps the sensor warm. If the O2 sensor cannot reach its operating temperature, it cannot properly measure the level of oxygen.
When the ECU detects that the oxygen sensor is not up to its working temperature it will trigger a P0036 code. Although the P0036 error code is a signal of a problem with a heating element of the downstream O2 sensor, it is not the sole cause for it.
Which Vehicles Are Most Prone to the P0036 Code?
Problems with oxygen sensors and their heater control circuits are very common. They are exposed to heat, vibrations, and different types of debris. That is why it is difficult to pinpoint the exact models that are prone to this type of problem. Every car owner needs to know that at some moment in their driving career will have this type of problem.
Causes of Trouble Code P0036
The root causes of P0036 fault codes are problems with the oxygen sensor or its heater control circuit. So when checking, pay attention to these issues:
- A faulty sensor in Bank 1 (part of the engine where the #1 cylinder is located). Sensor 2 points to a problem with the downstream sensor
- Defective wiring to the oxygen sensor
- Blown fuse for the oxygen sensor
- The exhaust doesn’t have a ground wire, or it has gone bad.
Common Reasons for the P0036 Code to Appear
Oxygen sensors are fully exposed to all sorts of environmental factors. They can get soaked in water. If the road is bad, they will feel the vibrations. They can get covered in mud or other debris. All those factors impact their work life.
The wiring harness can get damaged causing a problem in communication with the electronic control module (ECU). The connectors often get loose from all the vibrations, and if they are exposed to water they can get corroded. This also results in communication issues.
In some rare cases melted fuse for the oxygen sensor will cause the sensor to stop working. This can happen because of a power surge, or in case water penetrates in the fuse.
The whole exhaust system is maybe the most exposed part of the vehicle. The electronics of this system are often in danger of damage. If the exhaust system doesn’t have a good ground wire, it will cause several system problems, including the O2 sensor issues.
Check Out What Causes Engine Code P0036? (Hint: Oxygen Sensor):
Role of Oxygen Sensors and Heated Oxygen Sensors
The P0036 error code signals a problem with the emission control system. This system is composed of several parts like the EGR valve and the evaporative control system. But in this article, we will focus on the catalytic converter and the oxygen sensors.
The catalytic converter is inserted into the exhaust system. It is the most important part of the emission control system. All the exhaust gases go through the catalytic (CAT) converter where they are cleaned of most of the pollutants.
The CAT converter is made of beads composed of rhodium, palladium, and platinum. When bad pollutants like NOx, CO, and HC enter the converter, the beads split them up. When the CAT converter finishes its job, those bad gases are converted into harmful ones like H20, CO2, and N2.
Since CAT converters have a limited work life and can get damaged, something needs to control their work. There come the oxygen sensors. Depending on the car, the number of O2 sensors can vary between 2 and more than 4. One sensor is always located upstream from the CAT converter, and the other downstream.
The upstream sensor measures how much oxygen enters the CAT converter. The downstream sensor measures how much oxygen exited the CAT converter. Oxygen sensors monitor how the CAT converter works.
The O2 sensor heating element is responsible for heating the sensor quickly and keeping it constantly warm. The O2 sensor has to maintain a certain temperature so it can measure the presence the oxygen in the exhaust gases. When the O2 sensor heater circuit fails the ECU detects that the O2 sensor is cold. Then it triggers the P0036 error code.
There are other codes connected to problems with O2 sensor heater circuits, like the diagnostic codes P0037 and P0135.
HO2S Heater Control Circuit Bank 1 Sensor 2 Location
In Bank 1 Sensor 2 are two parameters to watch for when identifying the O2 sensor location. The Bank refers to the side of the engine. Bank 1 is the side of the engine where the #1 cylinder is located. The number of sensors refers to the position of the sensor. Sensor 2 is the oxygen sensor positioned after the catalytic converter.
Code P0036 Symptoms
P0036 error code doesn’t come with many identifiable symptoms.
- A turned-on check engine light. Often this is the only signal that there is a problem
- Failed emission test. When there is a problem with an O2 sensor, the car cannot pass the emission test
- The powertrain control module (PCM) initializing failsafe mode. In some rare cases, depending on the programmability of the PCM it can trigger a failsafe mode.
How to Diagnose the P0036 Code
The diagnostic process starts with testing the ECU for errors. Then the O2 sensor heater operation and condition are checked along with the whole O2 sensor. We will put this into a list of steps, which is easy to follow.
- Connect the vehicle to the OBD-II scanner. Run the scanner and wait until it tests the ECU for fault codes
- Delete the codes and go for a test drive. If the scanner has a freeze frame option, you can pinpoint the time and conditions that led to the P0036 code
- Locate the Bank 1 Sensor 2 location. You can find it on most cars in the exhaust pipe, behind the catalytic converter
- Check the condition of the sensor and its wiring. Look for any obvious damage to the sensor. Inspect the wiring and the connectors. If the wiring is flayed, or the insulation is burned off, that is a sign of bad wiring. Wiggle the connectors, to check if are they holding tight. Inspect them for any sign of corrosion
- Test the oxygen sensor heater circuit. Let the system cool down, and disconnect the oxygen sensor. For this operation, you will need a digital multimeter. Set it to measure resistance (ohms). The oxygen sensor usually comes with 4 wires. Two go directly to the heater element, while one is used for ground and the last one for the power supply. For safety purposes consult a wiring diagram. Use the multimeter to test the wires assigned to the heater circuit. When the circuit is cold, the readout on the multimeter should be between 10 and 20 ohms
- Test the oxygen sensor with the oscilloscope. Warm the engine to its operating temperature. Do not unplug the O2 sensor from the ECU. Connect the sensor output to the oscilloscope. Run the engine at around 2000 RPMs. If the oxygen sensor is working properly it should show a fluctuating voltage output between 0.1V and 1.0V. The time it takes it to move between the two values should be about 300 milliseconds. If the response time of the sensor is too slow, then the sensor is broken.
How Do I Fix Code P0036
After the diagnostics, the culprit for the error should be known. There are only two things that you can do:
- Replace the faulty wiring
- Replace the whole oxygen sensor.
If there are other symptoms besides the failed emission test, you should also inspect the ECU. In case there is a problem with the ECU, you should either try to reset it or in the worst case, replace it.
How to Reset the P0036 Code
If after replacing the faulty part, the error persists, the only thing you can do is to delete the code. To do this, you will need an OBD-II scanner. Once it identifies the error you can delete it. If it pops up again, then you should consult a mechanic for any other underlying problems.
Repair Options and Their Costs
- The price of the new oxygen sensor varies on the model and the sensor manufacturer. It can go anywhere between $30 and more than $300. The labor cost for replacing the sensor is typically between $100 and $150
- The wiring harness for the O2 sensor can cost anywhere between $20 and $80.
Check Out Car Electrical Problems: What Causes This Trouble?:
P0036 Code vs Other OBD-II Codes
The P0036 error code frequently comes with other emission system error codes. The most common are:
- P0030 – Heated Oxygen Sensor (H02S) Heater Control Circuit Bank 2 Sensor 1
- P0031 – Heated Oxygen Sensor (HO2S) Heater Circuit Low Voltage Bank 2 Sensor 1
- P0032 – Heated Oxygen Sensor (HO2S) Heater Circuit High Voltage Bank 2 Sensor 1
- P0037 – Heated Oxygen Sensor (HO2S) Heater Circuit Low Voltage Bank 2 Sensor 2
- P0038 – Heated Oxygen Sensor (HO2S) Heater Circuit High Voltage Bank 2 Sensor 2
- P0056 – Heated Oxygen Sensor (HO2S) Heater Circuit Bank 2 Sensor 2
- P0420 – Catalyst System Efficiency Below Threshold (Bank 1).
All these errors point to a problem with the emission system. Sometimes the problems with the CAT converter come together with the O2 errors.
FAQs
Can I Still Drive with a P0036 Code?
Yes, you can drive with a P0036 error code. You should not experience any performance issues. In case you need to go through with the emission test, fix this error beforehand. With this error, you will not be able to pass the test.
What Regulates The O2 Sensor Heating Circuit?
The ECU turns on the heater element for every oxygen sensor to look for any unexpected change in current. If the ECU measures values out of range, then it will pop out the code.
Need More Help With A P0036 Code?
Fixing a P0036 is usually a straightforward job. The problem is in most cases in the oxygen sensor itself. After diagnostics, you should find the sensor and its wiring the issue. You can resolve the problem by replacing the wiring or changing the sensor altogether.
But, if you are not familiar with DIY car mechanics, avoid doing anything alone. Contact a mechanic and get this problem fixed. Although it is not a major problem, it will still keep your car from passing the emission test. Also, the car will be emitting higher levels of bad pollutants into the air. Those are the reasons enough to get your car back in shape.
