AutoCodes – Mazda – P1173 Mazda

P1173 Mazda Code - HO2S-21 No Change Detected

Quick Answer

P1173 Mazda indicates HO2S-21 No Change Detected. Common causes include Faulty HO2S-21 Sensor, HO2S-21 Sensor harness is open or shorted, HO2S-21 Sensor circuit poor electrical connection. 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: P1173 Mazda indicates HO2S-21 No Change Detected.
Common causes: Common causes include Faulty HO2S-21 Sensor, HO2S-21 Sensor harness is open or shorted, HO2S-21 Sensor circuit poor electrical connection.
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 8,595

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

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Table of contents Created and updated by William Orellana on May 16, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1173 Mazda Description

OBDII Code P1173 Mazda - HO2S-21 No Change Detected - AutoCodes.com — P1173 Mazda Code - HO2S-21 No Change Detected

What does this mean?

What are the Possible Causes of the DTC P1173 Mazda?

Faulty HO2S-21 Sensor
HO2S-21 Sensor harness is open or shorted
HO2S-21 Sensor circuit poor electrical connection

How to Fix the DTC P1173 Mazda?

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 P1173 Mazda 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 P1173 Mazda Code

1. What does OBDII code P1173 mean for a Mazda?

P1173 indicates that the HO2S-21 (Heated Oxygen Sensor 2, Bank 1) is not detecting expected changes in the oxygen levels, suggesting a potential problem with the sensor or fuel system.

2. What are common symptoms of code P1173 in a Mazda?

Symptoms may include reduced engine performance, poor fuel economy, rough idling, hesitation during acceleration, and an illuminated check engine light.

3. What causes the P1173 code in a Mazda?

Common causes include a faulty HO2S-21 sensor, exhaust leaks, wiring issues, a malfunctioning fuel injector, or an incorrect air-fuel mixture.

4. Can a dirty or damaged oxygen sensor trigger code P1173?

Yes, a dirty, damaged, or failing oxygen sensor can cause the HO2S-21 to stop detecting changes in oxygen levels, leading to this code.

5. Is it safe to drive a Mazda with the P1173 code?

Driving with this code is not recommended as it can lead to poor engine performance and potential damage to the catalytic converter over time.

6. How do I fix the P1173 code on a Mazda?

Repairs may include replacing the oxygen sensor, fixing wiring or connector issues, repairing exhaust leaks, or addressing fuel system problems.

7. How can I diagnose the P1173 code in a Mazda?

Start by scanning for codes, inspecting the HO2S-21 sensor and its wiring, checking for exhaust leaks, and verifying the air-fuel mixture with a diagnostic tool.

8. Can a clogged fuel injector cause the P1173 code?

Yes, a clogged or malfunctioning fuel injector can disrupt the air-fuel mixture, leading to this code.

9. How much does it cost to repair a P1173 code in a Mazda?

Repair costs vary depending on the issue but typically range from $100 to $300 for parts and labor, with oxygen sensor replacement being the most common fix.

10. Will replacing the HO2S-21 sensor always fix the P1173 code?

Not always; while replacing the sensor often resolves the issue, underlying problems like wiring damage or fuel system faults may also need attention.