P0138 2017 Toyota RAV4 Code - Oxygen Sensor Circuit High Voltage Bank 1 Sensor 2
Quick Answer
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 Three-Way Catalytic Converter (TWC) is used. Common causes include Faulty Oxygen Sensor Bank 1 Sensor 2, Oxygen Sensor Bank 1 Sensor 2 harness is open or shorted, Oxygen Sensor Bank 1 Sensor 2 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
- P0138 2017 Toyota RAV4 indicates Oxygen Sensor Circuit High Voltage Bank 1 Sensor 2.
- Common causes
- Common causes include Faulty Oxygen Sensor Bank 1 Sensor 2, Oxygen Sensor Bank 1 Sensor 2 harness is open or shorted, Oxygen Sensor Bank 1 Sensor 2 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.
Code P0138 2017 Toyota RAV4 Description
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. more 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.
The ECM continuously monitors the heated oxygen sensor output voltage while the engine is running. The Diagnostic Trouble Code (DTC) P0138 is stored if the heated oxygen sensor voltage output is 1.2 V or higher for 10 seconds or more.
What are the Possible Causes of the DTC P0138 2017 Toyota RAV4?
- Faulty Oxygen Sensor Bank 1 Sensor 2
- Oxygen Sensor Bank 1 Sensor 2 harness is open or shorted
- Oxygen Sensor Bank 1 Sensor 2 circuit poor electrical connection
- Gas leak from exhaust system
How to Fix the DTC P0138 2017 Toyota RAV4?
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.
Code Tech Notes
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0138 2017 Toyota RAV4 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 P0138 2017 Toyota RAV4 code?
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Frequently Asked Questions about P0138 2017 Toyota RAV4 Code
What does the OBDII code P0138 mean on a 2017 Toyota RAV4?
P0138 indicates that the oxygen sensor (Bank 1, Sensor 2) is reporting a higher-than-normal voltage, suggesting an issue in the sensor circuit or exhaust system.
What are the symptoms of code P0138 on a 2017 Toyota RAV4?
Common symptoms include reduced fuel efficiency, rough idle, poor engine performance, or the illumination of the check engine light.
What causes the P0138 code on a 2017 Toyota RAV4?
Possible causes include a faulty downstream oxygen sensor, damaged wiring or connectors, excessive fuel mixture, or a malfunctioning catalytic converter.
Can I drive my 2017 Toyota RAV4 with the P0138 code?
Driving with P0138 may be possible for short distances, but prolonged use could lead to increased emissions, reduced fuel economy, or damage to engine components.
How do I fix the P0138 code on a 2017 Toyota RAV4?
Common fixes include replacing the oxygen sensor, repairing damaged wiring or connectors, checking for exhaust leaks, or addressing issues with the catalytic converter.
How do I test the oxygen sensor for the P0138 code?
You can test the oxygen sensor using a multimeter or scan tool to check its voltage readings and ensure it’s within the normal range (typically 0.1V to 0.9V).
Does a faulty oxygen sensor always trigger the P0138 code?
Not always. The code can also result from wiring issues, exhaust leaks, or problems with the catalytic converter affecting sensor readings.
How much does it cost to fix the P0138 code on a 2017 Toyota RAV4?
Repair costs can vary from $100–$300 for an oxygen sensor replacement to higher amounts if wiring repairs or catalytic converter work is needed.
Will clearing the P0138 code solve the issue?
Clearing the code will turn off the check engine light temporarily, but the underlying issue must be fixed to prevent the code from returning.
How can I prevent the P0138 code from appearing again?
Regular maintenance, inspecting wiring and connectors, ensuring proper fuel mixture, and addressing exhaust system issues can help prevent this code.
Discuss the causes and fixes for P0138 2017 Toyota RAV4 OBDII Code
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