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

Quick Answer

The P1138 diagnostic trouble code (DTC) indicates a lack of heated oxygen sensor switches for Bank 1 Sensor 2, with the sensor indicating a rich air-fuel mixture. Common causes include Faulty oxygen sensor, Wiring or connector issues, Exhaust leaks near the sensor. 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 indicates Lack Of Heated Oxygen Sensor Switches Bank 1 Sensor 2 Switch Indicates Rich.

Common causes

Common causes include Faulty oxygen sensor, Wiring or connector issues, Exhaust leaks near the sensor.

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.

• Description
• Common Causes
• Symptoms
• How To Fix
• Cost to Fix
• FAQs
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Common Causes of P1138

Symptoms of P1138

How to Fix P1138

Cost to Fix P1138

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Code P1138 Information for Specific Makes

• P1138 Audi — Long Term Fuel Trim Add. Fuel B2 System Too Lean
• P1138 BMW — O2 Sensor Heater Circuit Low Voltage Bank 1 Sensor 2
• P1138 Buick — HO2S Circuit High Voltage Sensor 2
• P1138 Cadillac — HO2S Circuit High Voltage Sensor 2
• P1138 Chevrolet — HO2S Circuit High Voltage Sensor 2
• P1138 Ford — Lack Of Heated Oxygen Sensor Switches Bank 1 Sensor 2 Switch Indicates Rich
• P1138 GMC — HO2S Circuit High Voltage Sensor 2
• P1138 Infiniti — Swirl Control Valve Control System Performance
• P1138 Isuzu — HO2S 2 Voltage Stays High Rich Condition
• P1138 Lincoln — Lack Of Heated Oxygen Sensor Switches Bank 1 Sensor 2 Switch Indicates Rich
• P1138 Mazda — Rear O2 Sensor Self Test Fault
• P1138 Mercury — Lack Of Heated Oxygen Sensor Switches Bank 1 Sensor 2 Switch Indicates Rich
• P1138 MINI — O2 Sensor Heater Circuit Low Voltage Bank 1 Sensor 2
• P1138 Nissan — Swirl Control Valve Control System Performance
• P1138 Pontiac — HO2S Bank 1 Sensor 2 Rich or High Voltage
• P1138 Saturn — HO2S Bank 1 Sensor 2 Rich or High Voltage
• P1138 Suzuki — HO2S Circuit High Voltage During Decel Fuel Cut-Off Sensor 2
• P1138 Volkswagen — Long Term Fuel Trim Add. Fuel B2 System Too Lean

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 Code

1. What are the common symptoms of OBDII code P1138?

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

2. What are the possible causes of OBDII code P1138?

- The code may be triggered by a faulty oxygen sensor, a vacuum leak, a fuel system issue, or a problem with the engine's air intake system.

3. How can I diagnose the root cause of OBDII code P1138?

- To diagnose the issue, you can use an OBDII scanner to read the code and then perform a visual inspection of the oxygen sensor, vacuum lines, and air intake system.

4. What does it mean when the code P1138 indicates "Lack Of Heated Oxygen Sensor Switches Bank 1 Sensor 2 Switch Indicates Rich"?

- This means that the oxygen sensor downstream of the catalytic converter on bank 1 is detecting a rich air-fuel mixture.

5. Can I drive with OBDII code P1138 present in my vehicle?

- It is not recommended to drive with this code present, as it can lead to further damage to the engine and the catalytic converter.

6. How do I repair OBDII code P1138?

- The repair process typically involves replacing the oxygen sensor on bank 1 sensor 2 and addressing any underlying issues such as vacuum leaks or fuel system problems.

7. Are there any DIY tips for fixing OBDII code P1138?

- While replacing the oxygen sensor may require some mechanical skill, checking for vacuum leaks or loose connections in the air intake system is something that can be done by a DIY enthusiast.

8. Can a dirty air filter cause OBDII code P1138 to appear?

- Yes, a dirty air filter can disrupt the air-fuel mixture ratio and potentially trigger code P1138, so it's important to check and replace the air filter if necessary.

9. How long does it typically take to repair OBDII code P1138?

- The repair time can vary depending on the exact cause of the code, but replacing the oxygen sensor usually takes around 1-2 hours.

10. Will resetting the OBDII code P1138 make it go away permanently?

- Resetting the code may temporarily turn off the check engine light, but if the underlying issue is not fixed, the code is likely to reappear. It's important to diagnose and repair the root cause of the problem.