AutoCodes – Mazda – P0059 Mazda

P0059 Mazda Code - HO2S21 Heater Control Circuit Fault

Quick Answer

The Heated Oxygen Sensor (HO2S) must reach the operating temperature to provide an accurate voltage signal. Common causes include Faulty heated oxygen sensor, Heated oxygen sensor harness open or shorted, Heated oxygen sensor circuit poor 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: P0059 Mazda indicates HO2S21 Heater Control Circuit Fault.
Common causes: Common causes include Faulty heated oxygen sensor, Heated oxygen sensor harness open or shorted, Heated oxygen sensor circuit poor 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 5,298

How popular is this code, among other codes? Low

Repair Importance Level

Moderate (Service soon) (2 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jul 13, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0059 Mazda Description

The Heated Oxygen Sensor (HO2S) must reach the operating temperature to provide an accurate voltage signal. A heating element inside the HO2S minimizes the time required for the sensor to reach operating temperature. With the engine running, the ground is provided to the heater by the HO2S heater low control circuit through a low side driver within the Powertrain Control Module (PCM). The PCM commands the heater ON or OFF to maintain a specific HO2S operating temperature range. The PCM determines the temperature by measuring the current flow through the heater. When the heater is in the ON state, the PCM will pulse the heater OFF for 50 ms, once per second. The PCM calculates the heater resistance on a cold start. The Diagnostic Trouble Code (DTC) will set if the heater current requirements too low or high in the HO2S heater control circuit.

OBDII Code P0059 Mazda - HO2S21 Heater Control Circuit Fault - AutoCodes.com — P0059 Mazda Code - HO2S21 Heater Control Circuit Fault

What does this mean?

What are the Possible Causes of the DTC P0059 Mazda?

Faulty heated oxygen sensor
Heated oxygen sensor harness open or shorted
Heated oxygen sensor circuit poor connection

How to Fix the DTC P0059 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 P0059 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 P0059 Mazda Code

1. What are the common symptoms of OBDII code P0059 on a Mazda?

- Common symptoms include lower fuel efficiency, rough idling, engine misfires, and the illumination of the Check Engine light.

2. What does the OBDII code P0059 on a Mazda indicate?

- The code P0059 indicates a heater control circuit fault in the HO2S21 (Heated Oxygen Sensor Bank 2 Sensor 1) in the Mazda's exhaust system.

3. What are the possible causes of OBDII code P0059 on a Mazda?

- Possible causes include a faulty HO2S21 sensor, damaged wiring or connectors in the heater circuit, a blown fuse, or issues with the ECM (Engine Control Module).

4. How can I diagnose the OBDII code P0059 on my Mazda?

- Diagnosis involves checking the wiring and connectors of the HO2S21 sensor, testing the sensor's heater element for continuity, and verifying proper voltage supply to the sensor.

5. Can I drive my Mazda with the OBDII code P0059 present?

- It is generally not recommended to drive the vehicle with the P0059 code present, as it can lead to poor engine performance and potential damage to the catalytic converter.

6. How can I repair the HO2S21 heater control circuit fault on my Mazda?

- Repair may involve replacing the HO2S21 sensor, repairing any damaged wiring or connectors, checking and replacing fuses if necessary, and clearing the error code from the ECM.

7. Is it possible to reset the OBDII code P0059 on a Mazda without fixing the issue?

- While you can clear the code temporarily with an OBDII scanner, the Check Engine light is likely to come back on if the underlying issue is not addressed.

8. How much does it cost to repair the HO2S21 heater control circuit fault on a Mazda?

- The cost of repair can vary depending on the specific cause of the issue, but it may range from $100 to $300 for parts and labor.

9. Can a DIY enthusiast fix the OBDII code P0059 on a Mazda?

- Depending on your skill level and access to tools, you may be able to replace the HO2S21 sensor or repair wiring yourself. However, diagnosis and repair of ECM-related issues may require professional assistance.

10. How often does the HO2S21 heater control circuit fault occur in Mazdas?

- While not extremely common, the HO2S21 heater control circuit fault can occur in Mazdas due to sensor degradation, wiring issues, or ECM malfunctions.