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Engine-Codes – Ford – P0138 1997 Ford F150

P0138 1997 Ford F150 Code - O2 Sensor Circuit High Voltage Bank 1 Sensor 2

Quick Answer

The P0138 code for a 1997 Ford F150 indicates an issue with the O2 sensor circuit having high voltage on Bank 1 Sensor 2. Common causes include Faulty O2 sensor, Wiring issues or shorts in the O2 sensor circuit, Exhaust leaks near the O2 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 1997 Ford F150 indicates O2 Sensor Circuit High Voltage Bank 1 Sensor 2.
Common causes
Common causes include Faulty O2 sensor, Wiring issues or shorts in the O2 sensor circuit, Exhaust leaks near the O2 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 1997 Ford F150 Description

The P0138 code for a 1997 Ford F150 indicates an issue with the O2 sensor circuit having high voltage on Bank 1 Sensor 2. The O2 sensor, also known as the oxygen sensor, plays a crucial role in monitoring the oxygen levels in the exhaust gases. This specific sensor, Bank 1 Sensor 2, is typically located after the catalytic converter in the exhaust system.

OBDII Code P0138 1997 Ford F150 - O2 Sensor Circuit High Voltage Bank 1 Sensor 2
P0138 1997 Ford F150 Code - O2 Sensor Circuit High Voltage Bank 1 Sensor 2

Common Causes of P0138 1997 Ford F150

  1. Faulty O2 sensor
  2. Wiring issues or shorts in the O2 sensor circuit
  3. Exhaust leaks near the O2 sensor
  4. Engine running rich due to issues such as a faulty fuel injector or fuel pressure regulator
  5. Issues with the ECM or other related engine control systems

Symptoms of P0138 1997 Ford F150

  1. Decreased fuel efficiency
  2. Rough idle or stalling
  3. Check Engine Light illuminated
  4. Poor acceleration or performance
  5. Increased emissions

How to Fix P0138 1997 Ford F150

  1. Diagnose the issue by using a scan tool to check the O2 sensor readings and inspecting the sensor and wiring for any visible damage.
  2. Replace the Bank 1 Sensor 2 O2 sensor if it is determined to be faulty.
  3. Repair any wiring issues or shorts in the O2 sensor circuit.
  4. Address any underlying engine issues that may be causing the rich fuel mixture.
  5. Clear the code and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P0138 1997 Ford F150

The cost of repairing a P0138 code on a 1997 Ford F150 can vary depending on the specific cause of the issue. In general, the cost of replacing an O2 sensor can range from $100 to $200 for the part alone. Labor costs can add an additional $50 to $100 per hour, with the total repair cost typically falling between $200 and $400. It's important to note that these estimates are rough averages and actual costs may vary based on the location, vehicle make and model, and the specific repair shop chosen. It's recommended to obtain quotes from local auto repair shops for a more accurate cost estimate.

What does this mean?

Tech Notes for P0138 1997 Ford F150

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

The HO2S Sensor Signals are monitored for an over voltage fault. The code is set when HO2S signal voltage is 1.5 volts or greater.

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 1997 Ford F150 Code

1. What are the common symptoms of OBDII code P0138 on a 1997 Ford F150?

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

2. What does the O2 Sensor Circuit High Voltage Bank 1 Sensor 2 mean for a 1997 Ford F150?

- This code indicates that the downstream oxygen sensor in bank 1 (cylinder 1 side) is detecting a higher than normal voltage.

3. What are the possible causes of OBDII code P0138 on a 1997 Ford F150?

- Potential causes include a faulty oxygen sensor, wiring issues in the sensor circuit, exhaust leaks, engine misfires, or a malfunctioning engine control module.

4. How can I diagnose and repair OBDII code P0138 on my 1997 Ford F150?

- To diagnose this code, you can use a scan tool to check the oxygen sensor readings and inspect the sensor's wiring for any damage. Repair involves replacing the faulty oxygen sensor or addressing any wiring issues.

5. Can I drive my 1997 Ford F150 with OBDII code P0138?

- It is generally safe to drive the vehicle for a short period with this code, but prolonged driving can lead to decreased fuel efficiency and potential damage to the catalytic converter.

6. How much does it cost to repair OBDII code P0138 on a 1997 Ford F150?

- The cost of repairing this code can vary depending on the underlying issue. Replacing a faulty oxygen sensor can range from $100 to $300, while addressing wiring problems or other issues may increase the cost.

7. What happens if I ignore OBDII code P0138 on my 1997 Ford F150?

- Ignoring this code can lead to reduced fuel efficiency, engine performance issues, and potential damage to the catalytic converter over time.

8. Can a DIY enthusiast fix OBDII code P0138 on a 1997 Ford F150?

- Yes, a DIY enthusiast with the necessary tools and knowledge can typically replace the oxygen sensor or address wiring issues causing this code.

9. How often should the oxygen sensors be replaced on a 1997 Ford F150 to avoid OBDII code P0138?

- Oxygen sensors generally have a lifespan of around 60,000 to 100,000 miles. Regularly inspecting and replacing them at the recommended intervals can help prevent issues like code P0138.

10. Will resetting the check engine light resolve OBDII code P0138 on a 1997 Ford F150?

- Resetting the check engine light will only clear the code temporarily. To address the underlying issue causing code P0138, proper diagnosis and repair are necessary.

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