Engine-Codes - Toyota - P0031 TOYOTA

P0031 TOYOTA - Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 1

Repair Importance Level: 2/3
Repair Difficulty Level: 2/3  What is this?
Table of contents

P0031 TOYOTA Possible Causes

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

How is the P0031 TOYOTA code repair?

Start by checking the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.

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









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What is the cost to diagnose the P0031 TOYOTA code

Labor: 1.0

The cost to diagnose the P0031 TOYOTA code is 1.0 hour of labor. The auto repair labor rates vary widely across the country, and even within the same city. Most auto repairs shops charge between $75 and $150 per hour.

When is the code detected?

The P0031 is set when the ECM detects an excessively low voltage through the heated oxygen sensor heater circuit

Possible Symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)

P0031 TOYOTA Meaning

Air-Fuel Ratio (A/F)sensor need to reach a minimum operating temperature of 1200 degrees F to produce an accurate voltage signal. The faster the air-fuel ratio sensor reaches that temperature the faster the sensor will start sending an accurate signal to the Engine Control Module (ECM).
In order to achieve the require temperature, a heater element is included inside the air-fuel ratio sensor. The ECM controls the air-fuel ratio sensor heater element based on signals from the engine coolant temperature and engine load. The ECM controls the heater element circuit by allowing current flow to ground.
The ECM monitors the voltage signal received through the heater element circuit and determines the state of the circuit by comparing the voltage detected with the factory specifications.

More Information

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