P0036 OBD-II Trouble Code: Heater Oxygen Sensor Control (HO2S) Circuit (Bank 1, Sensor 2)

Our certified mechanics come to you · 12-month, 12,000-mile warranty

SCHEDULE P0036 DIAGNOSTIC Get a fair and transparent estimate upfront
Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0036 code

P0036 is a diagnostic trouble code (DTC) for "Heater Oxygen Sensor Control (HO2S) Circuit (Bank 1, Sensor 2)". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic for $70.00. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $30.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford$70.00$30.00
Toyota$70.00$30.00
BMW$70.00$30.00
SCHEDULE P0036 DIAGNOSTIC Get a fair and transparent estimate upfront

Check Engine Light

P0036 Trouble Code definition

P0036 is the code for Heater Oxygen Sensor Control (HO2S) Circuit (Bank 1, Sensor 2)

What the P0036 code mean?

P0036 means that for the engine to operate properly, the engine exhaust should have a specific air fuel ratio of 14.7 to 1 as determined by the heated oxygen sensors (HO2S), which detects the oxygen content of the exhaust.

This sensor data is calculated by the Engine Control Module (ECM) to adjust the correct amount of fuel delivered to the engine. A heater oxygen sensor is heated to make certain of a very high speed response to the ECM closed loop system, which helps decrease emissions during start up and when the engine is in warmup.

What causes the P0036 code?

If the code is cleared and reset, and then the Check Engine Light comes on and the OBD-II code comes back, the HO2S sensor for the engine bank 1 and sensor #2, which is downstream of the catalytic converter, is not sending the proper data to the ECM and may be defective or have defective wiring. It is quite unusual if the ECM has failed.

What are the symptoms of the P0036 code?

With the O2 heater circuit not working, the O2 sensor response time will be affected and the sensor will not respond to fuel and oxygen in the exhaust for the first 3 to 5 minutes of running or more. The lack of response will affect the ECM’s ability to control the fuel mixture and it will go into a fixed fuel mix until the problem is fixed. The Check Engine Light will come on once the failure is detected by the ECM. The ECM will go into failsafe mode causing different drive symptoms depending on manufacture ECM programming.

How does a mechanic diagnose the P0036 code?

P0036 is diagnosed with an OBD-II scanner. The mechanic should reset the OBD-II code and test drive the vehicle to see if the code returns. If it comes back, the mechanic should check both power and ground to the sensor including closely inspecting the wiring and sensor. Many of the problems on this code are wiring related due to the heat of the exhaust damaging other components.

Common mistakes when diagnosing the P0036 code.

Do not assume that you should replace the HO2S before checking the all the related wiring and the connector closely. The mechanic should ensure there is 12 volts to the sensor and the ground is good. He must check both sides of the connector wiring to ensure the connector is good and not damaged.

How serious is the P0036 code?

The P0036 code will usually be preceded by the Check Engine Light coming on the vehicle’s dash while it is in operation. The vehicle can still be driven but it should properly be diagnosed as soon as possible to prevent potential problems like the sensor loop failing, excessive fuel consumption, poor operation, or damage to other components.

Often times, if the Check Engine Light came on immediately at start up, the OBD-II system can be reset and the vehicle will operate normally.

What repairs can fix the P0036 code?

The most common repairs to address the P0036 code are as follows:

  1. Have a certified technician verify the code with a scanner. Reset the fault codes and then perform a road test.

  2. If the P0036 code returns, then follow the test procedure. It can have several problems, but wiring being damaged by excessive heat from the exhaust is most common. Make certain the wiring is in good condition and has proper voltage and ground to the sensor before replacing the sensor.

Test Procedure:

With key on and the engine off, use a digital voltmeter to check for 12+ volts fused battery feed to the heater element. If there is no voltage present, repair any open or short in the 12 volt feed circuit, but first determine if it is necessary to replace any fuse blown from the short. If the battery feed is correct, remove the ground (control) circuit from the ECM wiring connector and check for resistance on the circuit. If there is infinite resistance, repair the open in the circuit. If the control circuit is good, suspect a bad HO2 sensor. Replace and re-check.

I have found this problem to be a fairly common code that is usually caused by the wiring touching the exhaust system and shorting out the power wire or sensor circuit. Vehicles normally have small wiring clamps on the chassis to hold the wiring away from the exhaust but many are plastic and cannot withstand the heat of the catalytic converter, then fail allowing the wiring to touch the exhaust or worse, the catalytic converter.

If melted, replace the wiring with the correct type of wire, not general electric wiring. Another issue is where a mechanic may have damaged the sensor if it was removed and reinstalled. A common problem can occur when the sensor is removed and damage is done to the female threads on the exhaust, which will require a special tap to repair the threads. But if they are too damaged, a new threaded insert must be welded on the exhaust. Remember these #2 HO2 sensors experience very high heat being at the outlet of the catalytic converter.

Additional comments for consideration regarding the P0036 code.

Many vehicles with mileage over 100,000 have momentary sensor problems that usually occur during start up or prolonged stress situations on the drive train. If the Check Engine Light comes on and the vehicle seems to be operating normally, the OBD-II system can be reset using the scanner and the problem may not reoccur. This is why it is important to verify the fault and reset it before doing any repairs.

Need help with a P0036 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230 to have this issue resolved.

Check Engine Light
trouble codes
P0036

Fast and easy Check Engine Light is on Inspection service at your home or office.

SCHEDULE P0036 DIAGNOSTIC
Get a fair and transparent estimate upfront

Recent Check Engine Light is on Inspection reviews

Excellent Rating


YourMechanic Check Engine Light is on Inspection Service

Average Rating

4.5/5

Number of Reviews

3,484

Rating Summary
3,176
153
40
23
92
3,176
153
40
23
92

Richard

10 years of experience
415 reviews
Richard
10 years of experience
This is the second time I’ve had Richard work on my car. He always does an outstanding job and is quick, knowledgeable and professional. Highly recommended!!
2012 DODGE CHALLENGER - CHECK ENGINE LIGHT IS ON - LAS VEGAS, NEVADA

Michael

13 years of experience
372 reviews
Michael
13 years of experience
Mike was an absolute professional when he arrived. He walked me thru the whole process of my repairs and also made good recommendations for preventive issues. His mechanical knowledge and good customer services was a breath of air and greatly appreciated :-)
2007 CHEVROLET AVALANCHE - CHECK ENGINE LIGHT IS ON INSPECTION - MARIETTA, GEORGIA

Rodrigo

10 years of experience
85 reviews
Rodrigo
10 years of experience
Rodrigo was exactly on time, very professional and friendly. He assessed my car, let me know the exact problem when a previous mechanic from a shop in my area was unable to. I felt he was very honest and sincere letting me know the level of urgency that I deal with the issue. Absolutely no pressure. I will absolutely use Rodrigo the next time I need anything to do with my car and will tell everyone about him. This is such a great service, I will never go to another mechanic again. It is so convenient. I couldn’t be happier. :)
2013 SMART FORTWO - CHECK ENGINE LIGHT IS ON - LAS VEGAS, NEVADA

Ricardo

8 years of experience
223 reviews
Ricardo
8 years of experience
Great service and was very helpful on what maintenance my vehicle needed and what to expect in the future. Would definitely recommend to anyone and will.
2004 MITSUBISHI LANCER - CHECK ENGINE LIGHT IS ON - LOS ANGELES, CALIFORNIA

More related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
P0222 OBD-II Trouble Code: Throttle/Pedal Position Switch/Sensor B Circuit Low Input
P0222 code definition Throttle/Pedal Position Switch/Sensor B Circuit Low Input What the P0222...
Veteran and Military Driver Laws and Benefits in New Mexico
The state of New Mexico offers a number of benefits and perks for those Americans who have either served in an Armed Forces branch...

Related questions

Q: When I accelerate quickly the Check Engine Light comes on.

This may be related to many different things, such as a failing throttle position sensor or a bad mass air flow sensor. The throttle position sensor relays the position of the throttle plate relative to your foot's position on the...

Q: Car loses power and stalls - 2014 Cadillac ATS

Hi! You may have to leave your vehicle with the dealership in order for them to be able to duplicate the concern. While it is not necessary for there to be diagnostic trouble codes present in the vehicle's computer in...

Q: Are the variable valve timing solenoid and the camshaft sensor the same?

Hello. The variable valve timing and the camshaft position sensor are two separate sensors. The camshaft position sensor is more towards the front of the engine and is a lot easier to replace. The variable valve timing sensor is a...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1-800-701-6230 · hi@yourmechanic.com