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P0138 Lexus Code - Oxygen Sensor Circuit High Voltage Bank 1 Sensor 2

Quick Answer

The P0138 code for a Lexus indicates an issue with the oxygen sensor circuit on Bank 1 Sensor 2. Common causes include Faulty oxygen sensor, Wiring or connector issues, Exhaust leaks near the oxygen sensor. 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 Lexus indicates Oxygen Sensor Circuit High Voltage Bank 1 Sensor 2.
Common causes
Common causes include Faulty oxygen sensor, Wiring or connector issues, Exhaust leaks near the oxygen sensor.
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.
What is this?
Table of contents Created and updated by William Orellana on Sep 08, 2024
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Code P0138 Lexus Description

The P0138 code for a Lexus indicates an issue with the oxygen sensor circuit on Bank 1 Sensor 2. This means that the oxygen sensor located downstream of the catalytic converter on the first bank of cylinders is reporting a high voltage condition. The oxygen sensor is responsible for measuring the amount of oxygen in the exhaust gases and providing feedback to the engine control module (ECM) to adjust the air-fuel mixture for optimal combustion. When the sensor reports a high voltage, it means that the exhaust gases are too lean, which can lead to inefficient combustion and increased emissions.

OBDII Code P0138 Lexus - Oxygen Sensor Circuit High Voltage Bank 1 Sensor 2
P0138 Lexus Code - Oxygen Sensor Circuit High Voltage Bank 1 Sensor 2

Common Causes of P0138 Lexus

  1. Faulty oxygen sensor
  2. Wiring or connector issues
  3. Exhaust leaks near the oxygen sensor
  4. Engine running too lean
  5. Faulty ECM

Symptoms of P0138 Lexus

  1. Decreased fuel efficiency
  2. Rough idling or stalling
  3. Engine misfires
  4. Increased emissions
  5. Check Engine Light illuminated

How to Fix P0138 Lexus

  1. Use a scan tool to confirm the P0138 code and identify the specific oxygen sensor causing the issue.
  2. Inspect the wiring and connector for any damage or corrosion. Repair or replace as necessary.
  3. Check for exhaust leaks near the oxygen sensor and repair them.
  4. Replace the Bank 1 Sensor 2 oxygen sensor with a new, OEM-quality unit.
  5. Clear the code and perform a test drive to verify that the issue has been resolved.

Cost to Fix P0138 Lexus

The cost of repairing a P0138 code on a Lexus can vary depending on the specific model and the labor rates in your area. In general, the price of a new oxygen sensor can range from $50 to $200, depending on the brand and quality. Labor costs for this repair can typically range from $100 to $300, depending on the shop's hourly rates and the complexity of the job. Therefore, the total cost of repairing a P0138 code on a Lexus could be anywhere from $150 to $500. It is recommended to get quotes from local auto repair shops to get a more accurate estimate.

What does this mean?

Tech Notes for P0138 Lexus

Replacing the Oxygen Sensor Bank 1 Sensor 2 (Rear Oxygen Sensor Bank 1 or Downstream Oxygen Sensor Bank 1) usually takes care of the problem.

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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 P0138 Lexus Code

1. What are the common symptoms of OBDII code P0138 in a Lexus related to the Oxygen Sensor Circuit High Voltage Bank 1 Sensor 2?

- Common symptoms include poor fuel economy, rough idling, loss of power, and the illumination of the Check Engine Light.

2. What are the potential causes of OBDII code P0138 in a Lexus?

- The code P0138 in a Lexus is typically triggered by a faulty oxygen sensor, damaged wiring or connectors, exhaust leaks, or issues with the engine's computer.

3. How can I diagnose the Oxygen Sensor Circuit High Voltage Bank 1 Sensor 2 issue in my Lexus?

- Diagnosis involves using an OBDII scanner to retrieve the specific fault code, inspecting the oxygen sensor and related wiring for damage, and checking for exhaust leaks.

4. Can a faulty oxygen sensor cause the OBDII code P0138 in a Lexus?

- Yes, a faulty oxygen sensor, particularly Bank 1 Sensor 2, can trigger the high voltage condition leading to the P0138 code.

5. What are some repair tips for addressing OBDII code P0138 in a Lexus?

- Repair tips include replacing the faulty oxygen sensor, repairing damaged wiring or connectors, fixing any exhaust leaks, and resetting the Check Engine Light.

6. Is it safe to continue driving my Lexus with the OBDII code P0138 related to the Oxygen Sensor Circuit High Voltage Bank 1 Sensor 2?

- It is generally not recommended to drive with the P0138 code as it can lead to decreased fuel efficiency and potential damage to the catalytic converter.

7. How much does it typically cost to repair OBDII code P0138 in a Lexus?

- The cost of repairing the P0138 code can vary depending on the specific issue, but it may range from $100 to $300 for parts and labor.

8. Can I reset the Check Engine Light after fixing the OBDII code P0138 in my Lexus?

- Yes, after addressing the underlying issue causing the P0138 code, you can reset the Check Engine Light using an OBDII scanner or by disconnecting the car's battery for a few minutes.

9. Are there any DIY solutions for fixing the OBDII code P0138 in a Lexus?

- While some may attempt DIY repairs for the P0138 code, it is recommended to consult a professional mechanic due to the complexity of diagnosing and repairing issues related to oxygen sensors and engine components.

10. How long does it typically take to repair the Oxygen Sensor Circuit High Voltage Bank 1 Sensor 2 issue causing OBDII code P0138 in a Lexus?

- The repair time for addressing the P0138 code can vary depending on the specific cause, but it may take anywhere from 1 to 3 hours at a repair shop.

Discuss the causes and fixes for P0138 Lexus OBDII Code

Submit a New Comment

  • tengo una lexus gx 470 modelo 2007.. el problema empeso cuando reemplase el exosto porque se rompio, en el taller cambiaron exactamente despues del O2 posterior de cada banco y el codigo empeso a estableserce como (baja eficiencia del catalizador banco 1)
    intercambie los sensores de O2 y persistia el codigo en el banco 1. luego reemplace el catalizador del banco por otro generico y ahora el codigo que se presenta es P0138, (voltage alto en el sensor O2 banco1 sensor 2), en ralenti permanese en 850mv mientras el otro permanese en 200mv , invierto los sensores y ocurre lo mismo..podria afectar la forma como empalmaron los tubos porque estos se unen en un solo tubo y no me parese que eso quedo como estaba anteriormente?

    Reply to Comment

  • Si puede afectar. Tambien si tiene alguna fuga en el exhaust puede afectar.

    Reply to Comment

  • i have lexus is 250 w/heather then a have a code for over heater sensor what can i do ..

    Reply to Comment

  • You probably have to replaced the rear oxygen sensor to fix the problem,

    Reply to Comment