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Engine-Codes – Toyota – P0138 2002 Toyota Highlander

P0138 2002 Toyota Highlander Code - Oxygen Sensor Circuit High Voltage Bank 1 Sensor 2

Quick Answer

The P0138 code for a 2002 Toyota Highlander indicates an issue with the Oxygen Sensor Circuit High Voltage Bank 1 Sensor 2. Common causes include Faulty oxygen sensor, Wiring or connector issues in the oxygen sensor circuit, Exhaust leaks before 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 2002 Toyota Highlander indicates Oxygen Sensor Circuit High Voltage Bank 1 Sensor 2.
Common causes
Common causes include Faulty oxygen sensor, Wiring or connector issues in the oxygen sensor circuit, Exhaust leaks before 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 12, 2024
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Code P0138 2002 Toyota Highlander Description

The P0138 code for a 2002 Toyota Highlander indicates an issue with the Oxygen Sensor Circuit High Voltage Bank 1 Sensor 2. This means that the oxygen sensor located downstream of the catalytic converter in Bank 1 is sending a signal that is registering as too high of a voltage. The oxygen sensor plays a crucial role in monitoring the air-fuel ratio in the exhaust system, helping the engine control module (ECM) adjust the fuel mixture for optimal performance and emissions control.

OBDII Code P0138 2002 Toyota Highlander - Oxygen Sensor Circuit High Voltage Bank 1 Sensor 2
P0138 2002 Toyota Highlander Code - Oxygen Sensor Circuit High Voltage Bank 1 Sensor 2

Common Causes of P0138 2002 Toyota Highlander

  1. Faulty oxygen sensor
  2. Wiring or connector issues in the oxygen sensor circuit
  3. Exhaust leaks before the oxygen sensor
  4. Engine running rich or lean conditions
  5. Issues with the ECM

Symptoms of P0138 2002 Toyota Highlander

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

How to Fix P0138 2002 Toyota Highlander

  1. Begin by diagnosing the issue with a scan tool to confirm the P0138 code and pinpoint the exact cause.
  2. Inspect the oxygen sensor and its wiring for any signs of damage or corrosion. Replace the sensor if necessary.
  3. Check for exhaust leaks before the oxygen sensor and repair as needed.
  4. Clear the code from the ECM memory and test drive the vehicle to ensure the issue has been resolved.
  5. If the problem persists, further diagnostic testing may be required to identify any underlying issues with the engine or ECM.

Cost to Fix P0138 2002 Toyota Highlander

The cost of repairing a P0138 code on a 2002 Toyota Highlander can vary depending on the specific cause of the issue. In general, the cost of replacing an oxygen sensor can range from $100 to $250, including parts and labor. Additional costs may be incurred if wiring or other components need to be replaced. It is advisable to consult with a trusted mechanic or auto repair shop for a more accurate estimate based on the specific circumstances of the vehicle. Labor rates at auto repair shops typically range from $80 to $150 per hour, but can vary based on location and other factors.

What does this mean?

Tech Notes for P0138 2002 Toyota Highlander

Replacing the Rear Heated Oxygen Sensor Bank 1 usually takes care of the problem.

When is the Code Detected?

The P0138 code is set when the Engine Control Module (ECM) detects that the rear O2 sensor signal voltage remains excessively high for an extended period of time.

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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 2002 Toyota Highlander Code

1. What are the common symptoms of OBDII code P0138 on a 2002 Toyota Highlander?

- Common symptoms include poor fuel efficiency, rough idling, and the illumination of the check engine light.

2. What does the OBDII code P0138 for a 2002 Toyota Highlander indicate?

- The code P0138 indicates that there is a high voltage condition in the oxygen sensor circuit of Bank 1 Sensor 2.

3. What are the possible causes of OBDII code P0138 on a 2002 Toyota Highlander?

- Potential causes include a faulty oxygen sensor, damaged wiring or connectors, exhaust leaks, or issues with the engine's computer.

4. How can I diagnose the OBDII code P0138 on my 2002 Toyota Highlander?

- Diagnosis involves using an OBDII scanner to read the code, inspecting the wiring and connectors, and testing the oxygen sensor's voltage output.

5. Is it safe to drive my 2002 Toyota Highlander with OBDII code P0138?

- It is generally safe to drive the vehicle with this code, but it is recommended to address the issue promptly to prevent potential damage to the catalytic converter.

6. Can I repair OBDII code P0138 on my 2002 Toyota Highlander myself?

- Depending on your mechanical skills, you may be able to replace the oxygen sensor, check and repair wiring, or address other possible causes with the help of repair guides.

7. How much does it typically cost to repair OBDII code P0138 on a 2002 Toyota Highlander?

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

8. Are there any tips to prevent OBDII code P0138 from occurring again on my 2002 Toyota Highlander?

- Regularly inspecting and maintaining the oxygen sensors, ensuring proper engine performance, and addressing any issues promptly can help prevent the code from reoccurring.

9. Will resetting the check engine light resolve OBDII code P0138 on my 2002 Toyota Highlander?

- Resetting the check engine light may temporarily clear the code, but it is important to diagnose and fix the underlying issue to prevent the code from coming back.

10. How long does it take to repair OBDII code P0138 on a 2002 Toyota Highlander?

- Repair times can vary based on the specific cause of the code, but it typically takes a few hours to a half-day for a professional mechanic to diagnose and repair the issue.

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