AutoCodes – Toyota – P0031 Toyota

P0031 Toyota Code - Oxygen Air-Fuel Ratio Sensor Heater Control Circuit Low Bank 1 Sensor 1

Quick Answer

The Engine Control Module (ECM) uses information from the air-fuel ratio sensor to regulate the air-fuel ratio and keep it close to the stoichiometric level. Common causes include Faulty Air-Fuel Ratio (A/F) Sensor Bank 1 Sensor 1, Air-Fuel Ratio Sensor Bank 1 Sensor 1 harness is open shorted to ground, Air-Fuel Ratio Sensor Bank 1 Sensor 1 circuit poor electrical connection. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

What it means: P0031 Toyota indicates Oxygen Air-Fuel Ratio Sensor Heater Control Circuit Low Bank 1 Sensor 1.
Common causes: Common causes include Faulty Air-Fuel Ratio (A/F) Sensor Bank 1 Sensor 1, Air-Fuel Ratio Sensor Bank 1 Sensor 1 harness is open shorted to ground, Air-Fuel Ratio Sensor Bank 1 Sensor 1 circuit poor electrical connection.
Severity: Moderate - service should be scheduled soon.
Can I drive?: The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

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Code Popularity 265,476

How popular is this code, among other codes? High

Repair Importance Level

Moderate (Service soon) (2 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Aug 22, 2022

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes ▶
Cost to Diagnose
FAQs
Comments
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Code P0031 Toyota Description

The Engine Control Module (ECM) uses information from the air-fuel ratio sensor to regulate the air-fuel ratio and keep it close to the stoichiometric level. This maximizes the ability of the three-way catalytic converter to purify the exhaust gases.
The air-fuel ratio sensor detects oxygen levels in the exhaust gas and transmits the information to the ECM. The inner surface of the sensor element is exposed to the outside air. The outer surface of the sensor element is exposed to exhaust gas. The sensor element is made of platinum-coated zirconia and includes an integrated heating element.
The zirconia element generates a small voltage when there is a large difference in the oxygen concentrations between the exhaust gas and outside air. The platinum coating amplifies this voltage generation.
The air-fuel ratio sensor is more efficient when heated. When the exhaust gas temperature is low, the sensor cannot generate useful voltage signals without supplementary heating. The ECM regulates supplementary heating using a duty-cycle approach to adjust the average current in the sensor heater element. If the heater current is outside the normal range, the signal transmitted by the air-fuel ratio sensor becomes inaccurate. As a result, the ECM is unable to regulate the air-fuel ratio properly.
When the current in the air-fuel ratio sensor heater is outside the normal operating range, the ECM interprets this as a malfunction in the sensor heater and stores a Diagnostic Trouble Code (DTC).

OBDII Code P0031 Toyota - Oxygen Air-Fuel Ratio Sensor Heater Control Circuit Low Bank 1 Sensor 1 - AutoCodes.com — P0031 Toyota Code - Oxygen Air-Fuel Ratio Sensor Heater Control Circuit Low Bank 1 Sensor 1

What does this mean?

What are the Possible Causes of the DTC P0031 Toyota?

Faulty Air-Fuel Ratio (A/F) Sensor Bank 1 Sensor 1
Air-Fuel Ratio Sensor Bank 1 Sensor 1 harness is open shorted to ground
Air-Fuel Ratio Sensor Bank 1 Sensor 1 circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P0031 Toyota?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

There are Factory Service Bulletins for the following Toyota Models:

2004 Toyota Sienna
2004 Toyota Sienna Factory Service Bulletin OBDII Code P0031

2005-2007 Toyota Avalon
2007-2008 Toyota Camry
2005-2007 Toyota Avalon, 2007-2008 Toyota Camry Factory Service Bulletin OBDII Code P0031

User Submitted Video

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0031 Toyota code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0031 Toyota code?

Need more information on how to fix the P0031 Toyota code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0031 Toyota code diagnosed by a professional: Find a repair shop in your area

Information for Specific Toyota Models

P0031 2006 Toyota Camry — Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 1
P0031 2007 Toyota Camry — Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 1
P0031 2008 Toyota Camry — Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 1
P0031 2009 Toyota Camry — Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 1
P0031 2010 Toyota Camry — Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 1
P0031 2011 Toyota Camry — Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 1
P0031 2001 Toyota Corolla — Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 1 3ZZ-FE Engine
P0031 2002 Toyota Corolla — Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 1 3ZZ-FE Engine
P0031 2003 Toyota Corolla — Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 1 3ZZ-FE Engine
P0031 2004 Toyota Corolla — Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 1 3ZZ-FE Engine
P0031 2005 Toyota Corolla — Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 1 3ZZ-FE Engine
P0031 2006 Toyota Corolla — Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 1 3ZZ-FE Engine
P0031 2001 Toyota Highlander — Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 1
P0031 2002 Toyota Highlander — Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 1
P0031 2003 Toyota Highlander — Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 1
P0031 2004 Toyota Highlander — Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 1
P0031 2005 Toyota Highlander — Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 1
P0031 2006 Toyota Highlander — Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 1
P0031 2007 Toyota Highlander — Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 1
P0031 2004 Toyota Prius — Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 1
P0031 2005 Toyota Prius — Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 1
P0031 2006 Toyota Prius — Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 1
P0031 2007 Toyota Prius — Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 1
P0031 2008 Toyota Prius — Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 1
P0031 2009 Toyota Prius — Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 1
P0031 2013 Toyota RAV4 — Oxygen Air-Fuel Ratio Sensor Heater Control Circuit Low Bank 1 Sensor 1
P0031 2014 Toyota RAV4 — Oxygen Air-Fuel Ratio Sensor Heater Control Circuit Low Bank 1 Sensor 1
P0031 2015 Toyota RAV4 — Oxygen Air-Fuel Ratio Sensor Heater Control Circuit Low Bank 1 Sensor 1
P0031 2016 Toyota RAV4 — Oxygen Air-Fuel Ratio Sensor Heater Control Circuit Low Bank 1 Sensor 1
P0031 2017 Toyota RAV4 — Oxygen Air-Fuel Ratio Sensor Heater Control Circuit Low Bank 1 Sensor 1
P0031 2018 Toyota RAV4 — Oxygen Air-Fuel Ratio Sensor Heater Control Circuit Low Bank 1 Sensor 1

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0031 Toyota Code

1. What is OBDII code P0031 for a Toyota?

- OBDII code P0031 for a Toyota refers to the Oxygen Air-Fuel Ratio Sensor Heater Control Circuit Low Bank 1 Sensor 1.

2. What are the common symptoms of OBDII code P0031 on a Toyota?

- Common symptoms of P0031 include reduced fuel efficiency, rough idling, and an illuminated check engine light.

3. What causes the Oxygen Air-Fuel Ratio Sensor Heater Control Circuit Low Bank 1 Sensor 1 code on a Toyota?

- The most common causes of P0031 in a Toyota are a faulty oxygen sensor, damaged wiring or connectors, or a blown fuse related to the sensor heater circuit.

4. How can I diagnose the issue related to OBDII code P0031 on my Toyota?

- Diagnose P0031 by checking the oxygen sensor's wiring and connections, testing the sensor's resistance, and inspecting the fuse for the sensor heater circuit.

5. Can I still drive my Toyota with OBDII code P0031 present?

- It is generally safe to drive with P0031, but it is important to address the issue promptly to prevent potential damage to the catalytic converter and ensure optimal fuel efficiency.

6. How can I repair OBDII code P0031 on my Toyota?

- Repair P0031 by replacing the Bank 1 Sensor 1 oxygen sensor, repairing any damaged wiring or connectors, and ensuring the fuse related to the sensor heater circuit is intact.

7. Does clearing the OBDII code P0031 on my Toyota reset the check engine light?

- Clearing the P0031 code will reset the check engine light, but if the underlying issue is not resolved, the code may reappear and the light will illuminate again.

8. Is it recommended to use OEM parts when replacing the oxygen sensor for P0031 on a Toyota?

- It is recommended to use OEM or high-quality aftermarket parts when replacing the oxygen sensor to ensure proper functionality and compatibility with your Toyota's system.

9. What are some preventive maintenance tips to avoid OBDII code P0031 on a Toyota?

- Regularly inspect and maintain your Toyota's oxygen sensors, wiring, and related components to prevent issues that could trigger the P0031 code.

10. Can a DIY enthusiast fix OBDII code P0031 on a Toyota, or is professional help recommended?

- DIY enthusiasts with automotive repair experience can often fix P0031 by following repair guides and using the right tools, but if unsure, seeking professional help is advisable.

Discuss the causes and fixes for P0031 Toyota OBDII Code

Submit a New Comment

Bespinoza58
Date: April 18, 2012 at 5:58 pm

where is oxysen sensor bank 1 on toyota 4 runner 2007

Reply to Comment
OBDIITech
Date: April 18, 2012 at 11:08 pm

What engine is on your 4Runner?
First attached image is for the 6 cyl engine and second for the 4 cyl engine.

Reply to Comment
Cezaramaya
Date: May 17, 2012 at 6:09 pm

where is oxy,,sensor bank 1 o toyota tundra 8 cil,

Reply to Comment
OBDIITech
Date: May 25, 2012 at 6:40 pm

What year?

Reply to Comment
Supertex_nady
Date: May 27, 2012 at 3:28 pm

where is O2 sensor heater circuit bank 1 sensor 1 TOYOTA 2000 land curoser 8V 4700

Reply to Comment
OBDIITech
Date: May 27, 2012 at 8:44 pm

See attached image:

Reply to Comment
Roy
Date: June 15, 2012 at 1:56 am

where is O2 sensor heater circuit bank 1 sensor 1 TOYOTA 2004 Tacoma V6 3.4

Reply to Comment
OBDIITech
Date: June 26, 2012 at 9:06 pm

See attached image

Reply to Comment
Chung Tran2008
Date: June 29, 2012 at 1:02 am

image for camry 2004 v6 please

Reply to Comment
George
Date: July 20, 2012 at 6:56 am

image for a 2003 Toyota Tacoma 3.4L V6 O2 sensor 1 Bank 1

Reply to Comment
nady
Date: July 28, 2012 at 8:44 pm

my toyota land cruiser 2006 4700cc v8 we have a code engine no. P0171 SYSTEM TO LEAN Bank 1 , any help !!!!!!

Reply to Comment
colten
Date: January 20, 2013 at 7:31 am

where is an 02 sensor 1 bank 1 for a 2005 toyota camry code p0031

Reply to Comment
OBDIITech
Date: February 12, 2013 at 11:47 pm

Here is the only image I have for the sensor. I hope it helps.

Reply to Comment
OBDIITech
Date: February 12, 2013 at 11:48 pm

Here is the only image I have for the sensor for your 2005. I hope it helps.

Reply to Comment
OBDIITech
Date: February 12, 2013 at 11:52 pm

2003 Toyota Tacoma 3.4L V6 O2 Sensor Location. Please see the attached image.

Reply to Comment
Patrick Koffie
Date: August 1, 2013 at 6:57 am

where is p0031 bank 1 sensor for toyota sequoia 2004

Reply to Comment
OBDIITech
Date: August 3, 2013 at 2:54 am

Driver's side front.

Reply to Comment
HReis
Date: February 9, 2014 at 4:10 pm

Thanks for your info.

Reply to Comment
wayne
Date: March 28, 2014 at 11:00 am

i am getting p0031 sensor1 bank 1 2004 toyota tundra dc 4.7 v8 what side is this on?

Reply to Comment
OBDIITech
Date: March 30, 2014 at 8:27 pm

Driver side of the engine.

Reply to Comment
Dan
Date: October 1, 2014 at 2:37 am

I have p0031 in my 07 Camry v6 were the sensor located?ty

Reply to Comment
OBDIITech
Date: October 3, 2014 at 10:43 pm

Passenger side, on exhaust manifold, before the catalytic converter on.

Reply to Comment
murban
Date: October 10, 2014 at 12:07 pm

Can anyone help me locate bank 1 sensor 1 for a 2007 Rav4 V6?

Reply to Comment
OBDIITech
Date: October 11, 2014 at 5:42 am

Is on the back of the engine.

Reply to Comment
Andy
Date: December 24, 2014 at 10:22 am

Can anyone help me locate bank 1 sensor 1 for a 2005 Solara V6?

Reply to Comment
OBDIITech
Date: December 27, 2014 at 8:11 pm

Sensor 1 Bank 1 is behind the engine, between the engine and the firewall.

Reply to Comment
chris
Date: March 11, 2015 at 2:48 pm

Where would heated 02 sensor be on my 2007 avalon touring

Reply to Comment
OBDIITech
Date: March 11, 2015 at 10:07 pm

Here is an image of the front oxygen sensors ( Air-Fuel Ratio (A/F) Sensor )

Reply to Comment
Mark
Date: April 8, 2015 at 1:56 pm

got a 09 sienna with code p0031. already replaced air fuel sensor and checked fuse in curcuit. what is the most likely cause or solution?

Reply to Comment
OBDIITech
Date: April 8, 2015 at 9:03 pm

Usually the sensor takes care of the problem. Is there a chance that you may have replace the wrong side sensor? or the sensor you install was damage?
If all it's OK, then you may have to have the dealer reprogram the ECM for you with the latest program. Other than the sensor, the program it's more like the cause.

Reply to Comment
am
Date: May 6, 2015 at 5:56 pm

Toyota Yaris, 2009, 1NR-FE, Engine code P0031 -> changed heated oxygen sensor 1, MIL again switch on - P0031.What is a problem, please?

Reply to Comment
OBDIITech
Date: May 7, 2015 at 9:55 pm

Usually the sensor fix the problem. It's possible that the new sensor is damage. The sensors are very sensible and can easily get damage. If you or the part store drop the sensor, then it could be damage.

Reply to Comment
am
Date: May 11, 2015 at 6:41 am

Changed the heated oxygen sensor 1 is Bosch. The heated circuit of this sensor is Ri=10,5 Ohm/20°C, Denso: Ri = 5,5-6,0 Ohm. The current of the heated circuit is set by ECU between 0,8 - 10 A. The resistance/600°C of Bosch sensor is higher than Denso and the current is lower than 0,8 A -> switch on MIL P0031.
You are right, the sensor fix the problem, thank you.

Reply to Comment
OBDIITech
Date: May 13, 2015 at 8:20 pm

Great information. Thanks for sharing

Reply to Comment
GS
Date: August 21, 2015 at 5:25 pm

Looking for image of below in a 2003 Toyota Camry LE 4 cylinder and what parts are required for home install (if not recommended please explain) including socket
Heated oxygen sensor
Circuit low 1, sensor 1
code P0031

Reply to Comment
Amanda McGill
Date: September 7, 2015 at 2:32 pm

Heres some typical dumb questions, if anyone can answer them :)
I just bought a truck with a few things i need to get done to it. I'm def not a mechanic but have these codes coming up and was wondering if I should figured it out myself or take it in.
ABS wheel speed sensors
heated oxygen sensor P0031
control circuit low
bank 1 sensor
I'm reading on some posts but usually when i have friends work on my vehicles something else breaks. Is this easy enough to just youtube and do myself, and what exactly do they mean... just sensors right?

Reply to Comment
OBDIITech
Date: September 10, 2015 at 11:24 pm

What model and year is your Toyota? The P0031 code is easy to diagnose, usually replacing the sensor takes care of the problem. The ABS sensor is a bit more difficult to diagnose and I suggest to having a tech check that for you.

Reply to Comment
Amanda McGill
Date: September 10, 2015 at 11:31 pm

Thanks. I'm bringing it in actually. I found a fair priced mechanic. But it's a 2004.

Reply to Comment
Darvishvand Hushang
Date: January 17, 2016 at 4:13 pm

Thanks to the excellent and beautiful site

Reply to Comment
thebighomey
Date: March 4, 2016 at 9:04 pm

2004 4runner V6 Sport edition? O2 Heater control Circuit low B2S1(code) location? Thanks in advance.

Reply to Comment
tom_pixel
Date: September 9, 2016 at 9:48 pm

I replaced the sensor with a new one on B1 S1 , looking at the engine 2011 Tacoma 4 x 4
Bank 1 on left side ? Check engine light still on ? Sensor was the one in Front of Cat, started engine light still on. Removed and clean Neg Cable on battery , started engine light was off for a couple of seconds but came right back on ??
Dealer print out says P0031 B1S1, maybe I put new sensor on wrong bank ?

Reply to Comment
OBDIITech
Date: September 13, 2016 at 9:11 pm

Bank 1 is on the passenger side of the engine.

Reply to Comment
Sarindy Vong
Date: February 19, 2019 at 3:12 pm

Toyota camry 2003 Code P0031
I change new o2 sensor
change ECU and Relay, fuse ,wire ,good
but check Engine light still on ,
How to fix ?

Reply to Comment
OBDIITech
Date: February 19, 2019 at 11:31 pm

Let me see if I can find more information. Does your Camry have 4 (2.4) or 6 (3.0) cylinders? any exhaust leaks?

Reply to Comment
nicholas timewell
Date: April 16, 2020 at 11:23 am

gday all, i just replaced the bank 1 sensor 1 plug on my 2004 4runner 6cyl and the code remains... but now after reading some info here its possible i replaced the wrong one. i swapped out the sensor on the drivers side closet to the engine. yay or nay? cheers!

Reply to Comment
OBDIITech
Date: April 16, 2020 at 7:16 pm

The P0031 is for the #2 on the image below. (On the back of the engine). As far as I know (and according to my manual) both connectors are the same. If the connectors are the same, you should be able to swap the sensor.

Click here to enlarge image

Reply to Comment
John Doe
Date: December 17, 2020 at 6:32 pm

I have P0031 on 06 Avalon, which sensor and location? Part number?

Reply to Comment
OBDIITech
Date: December 18, 2020 at 2:48 am

The P0031 is for the Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 1, which is located on the back of the engine

Click here to enlarge image

Reply to Comment
Jim B
Date: February 20, 2021 at 4:25 am

How about Toyota Hilux 2011 2.5L diesel, bank 1 sensor 1 location ?

Reply to Comment
Olayinka Olaolu Martins
Date: August 13, 2021 at 8:12 am

image for a 2006 Toyota Avalon 3.4L V6 O2
Bank 1 Sensor 1

Reply to Comment
Olayinka Olaolu Martins
Date: August 13, 2021 at 8:18 am

image for a 2003 Toyota Avalon 3.4L V6 O2
Bank 1 Sensor 1. I need a Link to purchase the sensor. [email protected]. thanks

Reply to Comment
OBDIITech
Date: August 14, 2021 at 12:26 am

Unfortunately, I do not have the part number or where to order. You must purchase the sensor at your local Toyota dealer. Here is the only image I got; I hope it helps.

Click here to enlarge image

Reply to Comment