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

Our certified mechanics come to you · 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 $114.99 . Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.0 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 $114.99 $20.0
Toyota $114.99 $20.0
BMW $124.99 $20.0
SCHEDULE P0036 DIAGNOSTIC Get a fair and transparent estimate upfront

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
P0036
trouble codes

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P0036 code.

SCHEDULE P0036 DIAGNOSTIC
Get a $20 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating

(7400)

Rating Summary
6879
249
58
41
173
6879
249
58
41
173
 at YourMechanic

David

13 years of experience
393 reviews
David
13 years of experience
Chevrolet Malibu L4-2.4L - Check Engine Light is on Inspection - Marietta, Georgia
He explained everything to me in detail on what I needed to know about my car. Definitely recommend him for getting the job done.
 at YourMechanic

Raymond

37 years of experience
402 reviews
Raymond
37 years of experience
Toyota Camry L4-2.2L - Check Engine Light is on - Las Vegas, Nevada
Raymond did a great job however I was charged for two hours labor and he was only here less than 45 minutes. should I expect this on future appointments with your mechanic ?
 at YourMechanic

Shane

17 years of experience
217 reviews
Shane
17 years of experience
Volkswagen EuroVan V6-2.8L - Check Engine Light is on Inspection - Austin, Texas
Arrived on time. Explained the issues he found and how he will fix it. I have parts on order and will schedule an appointment to have Shane install the parts when they arrive.
 at YourMechanic

Kanstantsin

19 years of experience
51 reviews
Kanstantsin
19 years of experience
Ford F-150 V8-4.6L - Check Engine Light is on Inspection - Littleton, Colorado
Kanstantsin arrived early. Was very courteous and professional. Will highly recommend to anyone. Thank you Kanstantsin.


Related questions

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...

More related articles

P0507 OBD-II Trouble Code: Idle Control System RPM Higher Than Expected
P0507 code definition P0507 is a generic OBD2 diagnostic trouble code (DTC) referencing a fault within the idle control system. This code...
P2133 OBD-II Trouble Code: Throttle/Pedal Position Sensor/Switch F Circuit High Input
P2133 P2133 code definition The P2133 diagnostic trouble code indicates that there is an issue with the F circuit of the Throttle/Pedal Position sensor switch. Related Trouble Codes: P2120 (https://www.yourmechanic.com/article/p2120-obd-ii-trouble-code-throttle-pedal-position-sensor-switch-d-circuit-by-jay-safford) OBD-II Trouble Code: Throttle/Pedal Position Sensor/Switch D Circuit P2121 OBD-II...
P0894 OBD-II Trouble Code: Transmission Component Slipping
P0894 means there is an issue with the vehicle’s automatic transmission component due to low, empty, or dirty fluid, or faulty shift solenoids.

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 (855) 347-2779 · hi@yourmechanic.com