AutoCodesSubaru – P0133 Subaru

P0133 Subaru Code - Oxygen Sensor Circuit Slow Response Bank 1 Sensor 1

Quick Answer

This sensor is a Zirconia type sensor, used to monitor exhaust gases for the presence of oxygen. Common causes include Faulty Front Heated Oxygen Sensor Bank 1, Front Heated Oxygen Sensor Bank 1 harness is open or shorted, Front 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
P0133 Subaru indicates Oxygen Sensor Circuit Slow Response Bank 1 Sensor 1.
Common causes
Common causes include Faulty Front Heated Oxygen Sensor Bank 1, Front Heated Oxygen Sensor Bank 1 harness is open or shorted, Front 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 20,928
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Jul 25, 2020
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Code P0133 Subaru Description

This sensor is a Zirconia type sensor, used to monitor exhaust gases for the presence of oxygen. Depending on the level of oxygen in the exhaust stream, the oxygen sensor can inform the Engine Control Module of a rich or lean fuel mixture condition. The Engine Control Module (ECM) will then add or subtract the fuel trim to obtain an ideal mixture. The Diagnostic Trouble Code (DTC) will set when the oxygen sensor voltage signal response time slower than the specified time.
OBDII Code P0133 Subaru - Oxygen Sensor Circuit Slow Response Bank 1 Sensor 1 - AutoCodes.com
P0133 Subaru Code - Oxygen Sensor Circuit Slow Response Bank 1 Sensor 1

What are the Possible Causes of the DTC P0133 Subaru?

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

How to Fix the DTC P0133 Subaru?

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.

Code Tech Notes

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0133 Subaru 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.

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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 P0133 Subaru Code

What does the OBDII code P0133 mean on a Subaru?

P0133 indicates that the oxygen sensor (Bank 1 Sensor 1) has a slow response time when adjusting to changes in the air-fuel mixture.

What are the common symptoms of code P0133 in a Subaru?

Symptoms may include the check engine light turning on, reduced fuel efficiency, rough idling, or hesitation during acceleration.

What causes the P0133 code to appear on a Subaru?

Common causes include a failing oxygen sensor, exhaust leaks, damaged wiring or connectors, or a dirty mass airflow sensor.

Can I continue driving my Subaru with a P0133 code?

While it may not cause immediate damage, driving with this code can lead to poor fuel efficiency and potential long-term engine issues, so it’s best to address it promptly.

How do I fix the P0133 code on my Subaru?

Repairs may involve replacing the oxygen sensor, repairing damaged wiring, fixing exhaust leaks, or cleaning the mass airflow sensor.

How can I diagnose the P0133 code on my Subaru?

Use an OBDII scanner to confirm the code, inspect the oxygen sensor and wiring, check for exhaust leaks, and test the sensor’s voltage response with a multimeter.

Does a bad oxygen sensor always cause the P0133 code on a Subaru?

Not always. While it’s a common cause, issues like exhaust leaks or wiring problems can also trigger the code.

How much does it cost to fix the P0133 code on a Subaru?

Replacing an oxygen sensor typically costs $150–$400, depending on the part and labor rates. Additional repairs, like fixing exhaust leaks, may increase costs.

What is Bank 1 Sensor 1 on a Subaru?

Bank 1 Sensor 1 refers to the upstream oxygen sensor located before the catalytic converter on the side of the engine with cylinder 1.

Can a dirty air filter cause the P0133 code on a Subaru?

While uncommon, a dirty air filter can contribute to air-fuel mixture issues that may indirectly affect oxygen sensor performance.

Discuss the causes and fixes for P0133 Subaru OBDII Code

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