AutoCodes – Ford – P1138 1997 Ford F150

P1138 1997 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 1997 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 2,745

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 Jul 24, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1138 1997 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 1997 Ford F150 - Lack Of Heated Oxygen Sensor Switches Bank 1 Sensor 2 Switch Indicates Rich - AutoCodes.com — P1138 1997 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 1997 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 1997 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 1997 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 1997 Ford F150 code?

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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 1997 Ford F150 Code

1. What are the common symptoms of OBDII code P1138 in a 1997 Ford F150?

- Common symptoms include decreased fuel efficiency, rough idling, and a noticeable decrease in engine performance.

2. What does the OBDII code P1138 "Lack Of Heated Oxygen Sensor Switches Bank 1 Sensor 2 Switch Indicates Rich" mean for a 1997 Ford F150?

- This code indicates that the heated oxygen sensor in Bank 1, Sensor 2 is detecting a rich air-fuel mixture.

3. What are the possible causes of OBDII code P1138 in a 1997 Ford F150?

- Common causes include a faulty oxygen sensor, a vacuum leak, a malfunctioning fuel injector, or issues with the engine's air intake system.

4. How can I diagnose the OBDII code P1138 in my 1997 Ford F150?

- Use an OBDII scanner to retrieve the specific error code and then inspect the oxygen sensor, check for vacuum leaks, and test the fuel injectors for proper function.

5. Is it safe to continue driving my 1997 Ford F150 with the OBDII code P1138 present?

- It is not recommended to drive the vehicle with this code present, as it can lead to further engine damage and decreased fuel efficiency.

6. Can I repair the OBDII code P1138 in my 1997 Ford F150 myself?

- Depending on your automotive repair skills, you may be able to replace the faulty oxygen sensor or address a vacuum leak yourself. However, complex issues may require professional help.

7. How much does it typically cost to repair the OBDII code P1138 in a 1997 Ford F150?

- The cost of repairs can vary depending on the root cause of the issue. Simple fixes like replacing an oxygen sensor can range from $50 to $200, while more complex repairs may cost several hundred dollars.

8. Will resetting the check engine light make the OBDII code P1138 go away in a 1997 Ford F150?

- Resetting the check engine light without addressing the underlying issue will not solve the problem. The code may reappear once the vehicle is driven again.

9. How long does it take to repair the OBDII code P1138 in a 1997 Ford F150?

- The repair time can vary based on the complexity of the issue. Simple fixes like replacing an oxygen sensor can be done in an hour or two, while more extensive repairs may take longer.

10. Can a faulty catalytic converter cause the OBDII code P1138 in a 1997 Ford F150?

- While a faulty catalytic converter is not a common cause of code P1138, it can impact the overall efficiency of the exhaust system and should be checked if other issues are ruled out.