Engine-Codes - Generic - P105D

P105D - O2 Sensor Heater Circuit Performance Bank 2 Sensor 2 Stuck ON

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

P105D Possible Causes

  • Faulty O2 Sensor Heater Bank 2 Sensor 2
  • O2 Sensor Heater Bank 2 Sensor 2 harness is open or shorted
  • O2 Sensor Heater Bank 2 Sensor 2 circuit poor electrical connection
  • Faulty Engine Control Module (ECM)

How do I fix code P105D?

Check 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.

Cost of diagnosing the P105D code

Labor: 1.0

The cost of diagnosing the P105D 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.

Possible Symptoms

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

P105D Meaning

In order to obtain a high purification rate of the carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NOx) components in the exhaust gas, a TWC (Three-Way Catalytic Converter) is used. For the most efficient use of the TWC, the air fuel ratio must be precisely controlled so that it is always close to the stoichiometric air fuel level. For the purpose of helping the ECM to deliver accurate air fuel ratio control, a heated oxygen sensor is used.
The heated oxygen sensor is located behind the TWC, and detects the oxygen concentration in the exhaust gas. Since the sensor is integrated with the heater that heats the sensing portion, it is possible to detect the oxygen concentration even when the intake air volume is low (the exhaust gas temperature is low).
When the air fuel ratio becomes lean, the oxygen concentration in the exhaust gas is high. The heated oxygen sensor informs the ECM that the post-TWC air fuel ratio is lean (low voltage, i.e. less than 0.45 V).
Conversely, when the air fuel ratio is richer than the stoichiometric air fuel level, the oxygen concentration in the exhaust gas is low. The heated oxygen sensor informs the ECM that the post-TWC air fuel ratio is rich (high voltage, i.e. higher than 0.45 V). The heated oxygen sensor has the property of changing its output voltage drastically when the air fuel ratio is close to the stoichiometric level.
The ECM uses the supplementary information from the heated oxygen sensor to determine whether the air fuel ratio after the TWC is rich or lean, and adjusts the fuel injection duration accordingly. Thus, if the heated oxygen sensor is working improperly due to internal malfunctions, the ECM is unable to compensate for deviations in the primary air fuel ratio control.

P105D More Information

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Information for specific makes

  • P105D LEXUS O2 Sensor Heater Circuit Performance Bank 2 Sensor 2 Stuck ON
  • P105D TOYOTA O2 Sensor Heater Circuit Performance Bank 2 Sensor 2 Stuck ON

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