AutoCodes – Ford – P0138 2000 Ford F150

P0138 2000 Ford F150 Code - O2 Sensor Circuit High Voltage Bank 1 Sensor 2

Quick Answer

The Heated Oxygen Sensor 2 (HO2S) (Rear O2 Sensor), after three way catalyst (manifold), monitors the oxygen level in the exhaust gas on each bank. Common causes include Faulty Rear Heated Oxygen Sensor Bank 1, Rear Heated Oxygen Sensor Bank 1 harness is open or shorted, Rear Heated Oxygen Sensor Bank 1 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 2000 Ford F150 indicates O2 Sensor Circuit High Voltage Bank 1 Sensor 2.
Common causes: Common causes include Faulty Rear Heated Oxygen Sensor Bank 1, Rear Heated Oxygen Sensor Bank 1 harness is open or shorted, Rear Heated Oxygen Sensor Bank 1 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.

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Code Popularity 2,801

How popular is this code, among other codes? Low

Repair Importance Level

Moderate (Service soon) (2 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 14, 2020

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0138 2000 Ford F150 Description

The Heated Oxygen Sensor 2 (HO2S) (Rear O2 Sensor), after three way catalyst (manifold), monitors the oxygen level in the exhaust gas on each bank. For optimum catalyst operation, the air fuel mixture (air-fuel ratio) must be maintained near the ideal stoichiometric ratio. The HO2S output voltage changes suddenly in the vicinity of the stoichiometric ratio. The Engine Control Module (ECM) adjusts the fuel injection time so that the air-fuel ratio is nearly stoichiometric. The HO2S generates a voltage between 0.1 and 0.9 V in response to oxygen in the exhaust gas. If the oxygen in the exhaust gas increases, the air-fuel ratio becomes Lean. The ECM interprets Lean when the HO2S voltage is below 0.45 V. If the oxygen in the exhaust gas decreases, the air-fuel ratio becomes Rich. The ECM interprets Rich when the HO2S voltage is above 0.45 V.

OBDII Code P0138 2000 Ford F150 - O2 Sensor Circuit High Voltage Bank 1 Sensor 2 - AutoCodes.com — P0138 2000 Ford F150 Code - O2 Sensor Circuit High Voltage Bank 1 Sensor 2

What does this mean?

What are the Possible Causes of the DTC P0138 2000 Ford F150?

Faulty Rear Heated Oxygen Sensor Bank 1
Rear Heated Oxygen Sensor Bank 1 harness is open or shorted
Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection
Intake air leaks
Exhaust gas leaks
Inappropriate fuel pressure
Faulty fuel injectors

How to Fix the DTC P0138 2000 Ford F150?

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.

What does this mean?

Code Tech Notes

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.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0138 2000 Ford F150 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 2000 Ford F150 code?

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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 2000 Ford F150 Code

1. What are the common symptoms of OBDII code P0138 for a 2000 Ford F150?

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

2. What does the OBDII code P0138 indicate for a 2000 Ford F150?

- The code P0138 indicates a high voltage condition in the O2 Sensor Circuit for Bank 1 Sensor 2 in the exhaust system of the vehicle.

3. What are the possible causes of OBDII code P0138 in a 2000 Ford F150?

- Possible causes include a faulty O2 sensor, wiring issues in the O2 sensor circuit, exhaust leaks, engine misfires, or a problem with the engine control module.

4. How can I diagnose the O2 Sensor Circuit High Voltage issue in a 2000 Ford F150?

- You can use a scan tool to read the OBDII code P0138, visually inspect the O2 sensor and its wiring for any damage, and perform voltage tests to determine the exact cause of the high voltage condition.

5. Can I drive my 2000 Ford F150 with OBDII code P0138?

- It is not recommended to drive the vehicle for an extended period with the code P0138 as it can lead to poor engine performance and potential damage to the catalytic converter.

6. How can I repair OBDII code P0138 in my 2000 Ford F150?

- The repair typically involves replacing the Bank 1 Sensor 2 O2 sensor, repairing any damaged wiring, fixing exhaust leaks, and clearing the code with a scan tool.

7. What are some tips to prevent O2 sensor circuit high voltage issues in a 2000 Ford F150?

- Regular maintenance, such as replacing O2 sensors at recommended intervals, checking for exhaust leaks, and ensuring proper engine performance, can help prevent OBDII code P0138.

8. Can a DIY enthusiast fix OBDII code P0138 in a 2000 Ford F150?

- Depending on your level of expertise, you may be able to replace the O2 sensor or check for visible wiring issues, but more complex diagnostics and repairs may require professional assistance.

9. How long does it take to repair OBDII code P0138 for a 2000 Ford F150?

- The repair time can vary based on the exact cause of the issue, but replacing the O2 sensor or fixing wiring problems typically takes around 1-2 hours.

10. Will resetting the Check Engine Light resolve OBDII code P0138 in a 2000 Ford F150?

- Resetting the Check Engine Light may temporarily turn it off, but the underlying issue causing OBDII code P0138 will remain unresolved, leading to the light coming back on.