AutoCodes – Ford – P1138 2002 Ford F150

P1138 2002 Ford F150 Code - Lack Of Heated Oxygen Sensor Switches Bank 1 Sensor 2 Switch Indicates Rich

Quick Answer

The Heated Oxygen Sensor 2 (HO2S2) (Downstream), after the three-way catalyst (manifold), monitors the oxygen level in the exhaust gas on each bank. Common causes include Exhaust gas leaks, Faulty Heated Oxygen Sensor 2 (HO2S2) (Downstream) Bank 1, Heated Oxygen Sensor 2 Bank 1 harness is open or shorted. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P1138 2002 Ford F150 indicates Lack Of Heated Oxygen Sensor Switches Bank 1 Sensor 2 Switch Indicates Rich.
Common causes: Common causes include Exhaust gas leaks, Faulty Heated Oxygen Sensor 2 (HO2S2) (Downstream) Bank 1, Heated Oxygen Sensor 2 Bank 1 harness is open or shorted.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 2,741

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Aug 02, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1138 2002 Ford F150 Description

The Heated Oxygen Sensor 2 (HO2S2) (Downstream), after the 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 maintain near the ideal stoichiometric ratio. The HO2S2 output voltage changes suddenly in the vicinity of the stoichiometric ratio. The Powertrain Control Module (PCM) adjusts the fuel injection time so that the air-fuel ratio is nearly stoichiometric. The HO2S2 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 PCM interprets Lean when the HO2S2 voltage is below 0.45 V. If the oxygen in the exhaust gas decreases, the air-fuel ratio becomes Rich. The PCM interprets Rich when the HO2S2 voltage is above 0.45 V. The P1138 code will set when the PCM detects that the HO2S2 signal is above the voltage of range for an extended period.

OBDII Code P1138 2002 Ford F150 - Lack Of Heated Oxygen Sensor Switches Bank 1 Sensor 2 Switch Indicates Rich - AutoCodes.com — P1138 2002 Ford F150 Code - Lack Of Heated Oxygen Sensor Switches Bank 1 Sensor 2 Switch Indicates Rich

What does this mean?

What are the Possible Causes of the DTC P1138 2002 Ford F150?

Exhaust gas leaks
Faulty Heated Oxygen Sensor 2 (HO2S2) (Downstream) Bank 1
Heated Oxygen Sensor 2 Bank 1 harness is open or shorted
Heated Oxygen Sensor 2 Bank 1 circuit poor electrical connection
Inappropriate fuel pressure
Faulty fuel injectors

How to Fix the DTC P1138 2002 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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1138 2002 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 P1138 2002 Ford F150 code?

Need more information on how to fix the P1138 2002 Ford F150 code? Get Access to Factory Service Manuals

Need Help with the 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 P1138 2002 Ford F150 Code

1. What are common symptoms of OBDII code P1138 on a 2002 Ford F150?

The common symptoms include poor fuel economy, rough idling, and the Check Engine light illuminating on the dashboard.

2. What does the OBDII code P1138 on a 2002 Ford F150 indicate?

The code P1138 indicates that the Heated Oxygen Sensor (HO2S) Bank 1 Sensor 2 is detecting a rich air-fuel mixture in the exhaust system.

3. What are the possible causes of OBDII code P1138 on a 2002 Ford F150?

Possible causes include a faulty HO2S Bank 1 Sensor 2, issues with the fuel system such as a leaking injector or fuel pressure regulator, or a problem with the engine's air intake system.

4. How can I diagnose the OBDII code P1138 on my 2002 Ford F150?

Diagnosing the code involves using an OBDII scanner to retrieve the code, checking the live data for the HO2S Bank 1 Sensor 2, and performing a visual inspection of the sensor and related components.

5. What are some repair tips for fixing OBDII code P1138 on a 2002 Ford F150?

Repair tips include replacing the faulty HO2S Bank 1 Sensor 2, addressing any fuel system issues, checking and cleaning the MAF sensor, and ensuring there are no vacuum leaks in the intake system.

6. Can I continue driving my 2002 Ford F150 with the OBDII code P1138?

It is not recommended to continue driving with the P1138 code present, as it can lead to decreased fuel efficiency and potential damage to the catalytic converter over time.

7. How much does it typically cost to repair OBDII code P1138 on a 2002 Ford F150?

The cost of repair can vary depending on the exact cause of the code, but it may range from $200 to $500 for parts and labor.

8. Are there any recalls or technical service bulletins related to OBDII code P1138 on a 2002 Ford F150?

It's advisable to check with a Ford dealership or online resources for any recalls or technical service bulletins related to the specific issue indicated by code P1138 on the 2002 Ford F150.

9. Can a DIY enthusiast fix the OBDII code P1138 on a 2002 Ford F150?

Depending on the skill level and tools available, some DIY enthusiasts may be able to address the P1138 code by following repair guides and using the necessary diagnostic equipment.

10. How often should the Heated Oxygen Sensor Bank 1 Sensor 2 be replaced on a 2002 Ford F150?

The HO2S Bank 1 Sensor 2 should typically be inspected and replaced if necessary according to the manufacturer's recommended maintenance schedule, usually around 60,000 to 100,000 miles.