P0051 Infiniti Code - HO2S21 Heater Control Circuit Low
Quick Answer
The P0051 Infiniti diagnostic trouble code (DTC) specifically refers to an issue with the Heater Control Circuit of the HO2S21 sensor. Common causes include Faulty HO2S21 sensor, Damaged wiring or connectors in the Heater Control Circuit, Issues with the engine control module (ECM). 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
- P0051 Infiniti indicates HO2S21 Heater Control Circuit Low.
- Common causes
- Common causes include Faulty HO2S21 sensor, Damaged wiring or connectors in the Heater Control Circuit, Issues with the engine control module (ECM).
- 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 P0051 Infiniti Description
The P0051 Infiniti diagnostic trouble code (DTC) specifically refers to an issue with the Heater Control Circuit of the HO2S21 sensor. The HO2S21 sensor is located in the exhaust system and is responsible for monitoring the oxygen levels in the exhaust gases. The Heater Control Circuit is designed to heat the sensor quickly to operating temperature for accurate readings. When this circuit is detected to be operating at a lower voltage than specified, the P0051 code is triggered. This can lead to inaccurate oxygen level readings, which can negatively impact the engine's performance and emissions control system. If left unresolved, it can lead to reduced fuel efficiency, engine misfires, and potential damage to the catalytic converter.
Common Causes of P0051 Infiniti
- Faulty HO2S21 sensor
- Damaged wiring or connectors in the Heater Control Circuit
- Issues with the engine control module (ECM)
- Exhaust leaks near the sensor
- Corrosion or contamination on sensor connectors
Symptoms of P0051 Infiniti
- Check Engine Light illuminated on the dashboard
- Decreased fuel efficiency
- Rough idling or stalling
- Increased emissions levels
- Loss of engine power
How to Fix P0051 Infiniti
- Use a scan tool to verify the P0051 code and confirm the issue with the HO2S21 sensor.
- Inspect the wiring and connectors for any damage or corrosion. Repair or replace as necessary.
- Check for exhaust leaks near the sensor and repair if found.
- Test the HO2S21 sensor's heating element and replace if it fails.
- Clear the code and perform a test drive to ensure the issue has been resolved.
Cost to Fix P0051 Infiniti
The cost of repairing a P0051 Infiniti code can vary depending on the specific cause of the issue. In general, the cost of replacing the HO2S21 sensor can range from $100 to $300, while repairing wiring or connectors may cost around $50 to $100. Labor costs can add an additional $80 to $150 per hour, and the total repair bill could range from $150 to $500. It's important to note that these are rough estimates, and actual costs can vary based on factors such as location, vehicle make and model, and the extent of the repairs needed.
Tech Notes for P0051 Infiniti
When is the Code Detected?
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Information for Specific Infiniti Models
- P0051 2003 Infiniti G35 — HO2S21 Heater Control Circuit Low
- P0051 2004 Infiniti G35 — HO2S21 Heater Control Circuit Low
- P0051 2005 Infiniti G35 — Air Fuel Ratio Sensor 1 Heater Bank 2 Control Circuit Low
- P0051 2006 Infiniti G35 — Air Fuel Ratio Sensor 1 Heater Bank 2 Control Circuit Low
Frequently Asked Questions about P0051 Infiniti Code
1. What does the OBDII code P0051 mean on an Infiniti?
P0051 indicates a problem with the Heater Control Circuit Low in the Bank 2 Sensor 1 oxygen sensor, meaning the heater element is not functioning properly.
2. What are the common symptoms of P0051 in an Infiniti?
Symptoms include poor fuel efficiency, rough idling, reduced engine performance, and an illuminated Check Engine Light.
3. What causes the P0051 code to appear on an Infiniti?
Common causes include a faulty oxygen sensor, damaged wiring or connectors, a blown fuse, or issues with the engine control module (ECM).
4. Can I drive my Infiniti with the P0051 code?
While driving with P0051 may be possible, it is not recommended as it can lead to poor fuel economy and potential damage to the catalytic converter over time.
5. How can I fix the P0051 code on my Infiniti?
Repairs may involve replacing the oxygen sensor, repairing damaged wiring, checking fuses, or diagnosing the ECM for further issues.
6. How do I locate the Bank 2 Sensor 1 oxygen sensor on my Infiniti?
Bank 2 Sensor 1 is the upstream oxygen sensor on the side of the engine opposite Cylinder 1, typically located before the catalytic converter.
7. What tools are needed to diagnose and repair the P0051 code?
You’ll need an OBDII scanner, a multimeter to check voltage and resistance, and basic tools to replace the oxygen sensor if needed.
8. How do I test the oxygen sensor heater circuit for P0051?
Use a multimeter to check the resistance of the heater circuit in the oxygen sensor; a reading outside the manufacturer’s specifications indicates a faulty sensor.
9. Will clearing the P0051 code turn off the Check Engine Light permanently?
Clearing the code will temporarily turn off the light, but if the underlying issue isn’t fixed, the code and light will return.
10. How much does it cost to repair the P0051 code on an Infiniti?
Repair costs vary, but replacing an oxygen sensor typically ranges from $150 to $400, depending on parts and labor.
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