Engine-Codes - Mercedes-benz - P0159 MERCEDES-BENZ

P0159 MERCEDES-BENZ - O2 Sensor Circuit Slow Response Bank 2 Sensor 2

Repair Importance Level: 2/3
Repair Difficulty Level: 2/3  What is this?
Table of contents

P0159 MERCEDES-BENZ Possible Causes

  • Faulty Rear Heated Oxygen Sensor Bank 2
  • Rear Heated Oxygen Sensor Bank 2 harness is open or shorted
  • Rear Heated Oxygen Sensor Bank 2 circuit poor electrical connection

How is the P0159 MERCEDES-BENZ code repair?

Start by checking the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.

Tech Notes

Mercedes Benz Code = 0521 (Left O2 sensor, after TWC): Aging (P0159)

Replacing the O2 Sensor 2 usually takes care of the problem

What is the cost to diagnose the P0159 MERCEDES-BENZ code

Labor: 1.0

The cost to diagnose the P0159 MERCEDES-BENZ code is 1.0 hour of labor. The auto repair's diagnosis time and labor rates vary by location, vehicle's make and model, and even your engine type. Most auto repair shops charge between $75 and $150 per hour.
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When is the code detected?

The P0159 code is set when the Engine Control Module (ECM) detects that the rear O2 sensor takes more time to respond between rich and lean than the specified time.

Possible Symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)
  • High Fuel Consumption
  • Excessive Smoke from Exhaust


This fault code is stored in the engine control module when the oxygen sensor response time is not as expected. This condition occurs if the sensor has been contaminated or is suffering from ageing. The ECM expects a voltage shift within a specific time frame under transient conditions. The rise and fall time of the sensor is monitored for this.

More Information

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