P0166 Mercedes-Benz Code - O2 Sensor Circuit No Activity Detected Bank 2 Sensor 3
Quick Answer
The rear heated oxygen sensor (or sensor 3 for some vehicles), after three way catalyst (manifold), monitors the oxygen level in the exhaust gas on each bank. Common causes include Faulty Heated Oxygen Sensor Bank 2 Sensor 3, Heated Oxygen Sensor Bank 2 Sensor 3 harness is open or shorted, Heated Oxygen Sensor Bank 2 Sensor 3 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
- P0166 Mercedes-Benz indicates O2 Sensor Circuit No Activity Detected Bank 2 Sensor 3.
- Common causes
- Common causes include Faulty Heated Oxygen Sensor Bank 2 Sensor 3, Heated Oxygen Sensor Bank 2 Sensor 3 harness is open or shorted, Heated Oxygen Sensor Bank 2 Sensor 3 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.
Code P0166 Mercedes-Benz Description
What are the Possible Causes of the DTC P0166 Mercedes-Benz?
- Faulty Heated Oxygen Sensor Bank 2 Sensor 3
- Heated Oxygen Sensor Bank 2 Sensor 3 harness is open or shorted
- Heated Oxygen Sensor Bank 2 Sensor 3 circuit poor electrical connection
How to Fix the DTC P0166 Mercedes-Benz?
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 P0166 Mercedes-Benz 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.
Need more information about the P0166 Mercedes-Benz code?
Need more information on how to fix the P0166 Mercedes-Benz code? Get Access to Factory Service Manuals
Need Help with the Code?
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Frequently Asked Questions about P0166 Mercedes-Benz Code
1. What are the common symptoms of OBDII code P0166 in a Mercedes-Benz?
The common symptoms of code P0166 include poor fuel economy, rough idling, a noticeable decrease in engine performance, and the illumination of the check engine light.
2. What does the O2 Sensor Circuit No Activity Detected Bank 2 Sensor 3 error mean?
The P0166 code indicates that the O2 sensor located on Bank 2 Sensor 3 in your Mercedes-Benz is not sending any activity signals to the engine control module.
3. What are the possible causes of OBDII code P0166 in a Mercedes-Benz?
Possible causes of code P0166 include a faulty O2 sensor, damaged wiring or connectors in the O2 sensor circuit, issues with the power supply to the sensor, or a malfunctioning engine control module.
4. How can I diagnose the O2 sensor on Bank 2 Sensor 3 in my Mercedes-Benz?
To diagnose the O2 sensor on Bank 2 Sensor 3, you can use a multimeter to check for voltage output, visually inspect the sensor and its wiring for damage, or use a scan tool to monitor sensor data and performance.
5. Can I continue driving my Mercedes-Benz with OBDII code P0166?
It is not recommended to continue driving your vehicle with code P0166 present, as it can lead to further damage to the engine and emission control systems.
6. How can I repair OBDII code P0166 in my Mercedes-Benz?
Repairing code P0166 involves replacing the O2 sensor on Bank 2 Sensor 3, repairing any damaged wiring or connectors, ensuring a proper power supply to the sensor, and clearing the error code.
7. Will resetting the check engine light fix OBDII code P0166?
Simply resetting the check engine light will not fix the underlying issue causing code P0166. It is important to diagnose and repair the root cause of the problem to prevent the code from reappearing.
8. How much does it cost to repair OBDII code P0166 in a Mercedes-Benz?
The cost of repairing code P0166 can vary depending on the severity of the issue, the price of the replacement parts, and labor costs. It is recommended to consult a qualified mechanic for an accurate estimate.
9. Can a DIY enthusiast fix OBDII code P0166 in a Mercedes-Benz?
While some DIY enthusiasts may have the skills to replace the O2 sensor or check wiring connections, diagnosing and repairing code P0166 properly may require specialized tools and expertise best handled by a professional mechanic.
10. How often should I check the O2 sensors in my Mercedes-Benz to prevent OBDII code P0166?
It is recommended to inspect and test the O2 sensors in your Mercedes-Benz during routine maintenance or whenever you experience symptoms of poor engine performance to catch any potential issues early and prevent code P0166 from appearing.
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