O2 Sensor Circuit Malfunction Bank 1 Sensor 3
Table of contents
- Possible Causes
- How To Fix
- Tech Notes
- Cost To Diagnose
- When is the code detected
- Possible Symptoms
- Description
P0142 MERCEDES-BENZ Possible Causes
- Faulty Heated Oxygen Sensor Bank 1 Sensor 3
- Heated Oxygen Sensor Bank 1 Sensor 3 harness is open or shorted
- Heated Oxygen Sensor Bank 1 Sensor 3 circuit poor electrical connection
How do I fix code P0142 MERCEDES-BENZ?
Check 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
- Replacing the O2 Sensor 3 usually takes care of the problem
Cost of diagnosing the P0142 MERCEDES-BENZ code
The cost of diagnosing the P0142 MERCEDES-BENZ code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
When is the code detected
Current amperage in the rear heated oxygen sensor heater circuit is out of the normal range.
Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- High Fuel Consumption
- Excessive Smoke from Exhaust
P0142 MERCEDES-BENZ Description
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. Even if switching characteristics of the heated oxygen sensor 1 are shifted, the air-fuel ratio is controlled to stoichiometric, by the signal from the heated oxygen sensor 3.
This sensor is made of ceramic zirconia. The zirconia generates voltage from approximately 1V in richer conditions to 0V in leaner conditions. Under normal conditions the heated oxygen sensor 3 is not used for engine control operation.