P0138 2014 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 2014 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 2014 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 2014 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 2014 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 2014 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 2014 Toyota RAV4 code?
Need more information on how to fix the P0138 2014 Toyota RAV4 code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the P0138 2014 Toyota RAV4 code diagnosed by a professional: Find a repair shop in your area
Frequently Asked Questions about P0138 2014 Toyota RAV4 Code
1. What does the OBDII code P0138 mean for a 2014 Toyota RAV4?
P0138 indicates that the voltage from the downstream oxygen sensor (Bank 1, Sensor 2) is higher than the expected range, suggesting a potential issue with the sensor or related components.
2. What are the common symptoms of the P0138 code in a 2014 Toyota RAV4?
Symptoms may include poor fuel economy, increased emissions, a check engine light, and rough engine performance in some cases.
3. What causes the P0138 code in a 2014 Toyota RAV4?
Common causes include a faulty downstream oxygen sensor, damaged wiring or connectors, a rich fuel mixture, or a malfunctioning catalytic converter.
4. How do I diagnose the P0138 code on my 2014 Toyota RAV4?
Start by inspecting the oxygen sensor wiring and connectors for damage. Use a multimeter to check sensor voltage and verify proper function. A scan tool can also help monitor live data from the sensor.
5. Can driving with the P0138 code damage my 2014 Toyota RAV4?
Driving with this code for an extended period can lead to increased emissions, reduced fuel efficiency, and potential damage to the catalytic converter.
6. How can I fix the P0138 code on a 2014 Toyota RAV4?
Repairs may involve replacing the downstream oxygen sensor, repairing damaged wiring, or addressing issues with the catalytic converter or fuel system.
7. How much does it cost to fix the P0138 code on a 2014 Toyota RAV4?
The cost varies depending on the cause. Replacing the oxygen sensor typically costs $100–$300, while catalytic converter repairs could be more expensive.
8. Can a dirty air filter cause the P0138 code in a 2014 Toyota RAV4?
A dirty air filter alone is unlikely to trigger P0138, but it might contribute to a rich fuel mixture that exacerbates the problem.
9. Is it safe to clear the P0138 code without making repairs on a 2014 Toyota RAV4?
Clearing the code without repairs may temporarily turn off the check engine light, but the underlying issue will likely persist and return.
10. How do I prevent the P0138 code from appearing on my 2014 Toyota RAV4?
Regular maintenance, including checking oxygen sensors, wiring, and proper fuel system operation, can help prevent this code from occurring.
Discuss the causes and fixes for P0138 2014 Toyota RAV4 OBDII Code
Code P0138 2014 Toyota RAV4 comments
No comments found for this page.
Fix Your Car Smarter
Try the New AutoCodes App!
Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.
