Mercedes-Benz 400SE Oxygen Sensor Replacement at your home or office.

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Oxygen Sensor Replacement Estimate for Mercedes-Benz 400SE

Mercedes-Benz 400SE Oxygen Sensor Replacement costs $259 on average. Following is a breakdown of the labor and parts estimates.

YourMechanic Price
$258 to $268
Labor: $70 -$80
Parts: $188
Average Dealer price
$470
Average Shop price
$319
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Our mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing
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CarServiceYourMechanic PriceShop/Dealer Price
1992 Mercedes-Benz 400SEV8-4.2LService typeOxygen Sensor - Front/Upper/Upstream ReplacementYourMechanic Price$446.58Shop/Dealer Price$566.14 - $867.63
1992 Mercedes-Benz 400SEV8-4.2LService typeOxygen Sensor - Rear/Lower/Downstream ReplacementYourMechanic Price$446.58Shop/Dealer Price$566.26 - $867.84
Show example Mercedes-Benz 400SE Oxygen Sensor Replacement prices

Oxygen Sensor Replacement Service & Cost

What is the Oxygen Sensor all about?

With each new model year, manufacturers are adding more oxygen sensors to better manage engine operation. Some high performance engines have an oxygen sensor for each cylinder as well as one for the rear of each catalytic convertor. The sensors are located either underneath the hood or underneath the car. The oxygen sensors are connected (screwed) to the exhaust pipe, either in front or back of the catalytic converter. The front (upstream) sensors measure the amount of oxygen in the exhaust system. The purpose of the front oxygen sensor(s) is to measure how rich or lean the gases are as the gases exit the combustion chamber. Depending upon whether the exhaust gas is lean (high in oxygen content) or rich (low in oxygen content), the amount of fuel entering the engine is adjusted by the engine management computer to try and maintain an ideal mixture that produces the lowest emissions output from the catalytic convertor.

Rear (downstream) sensors are located behind the catalytic converter. The purpose of the rear oxygen sensor(s) is to monitor the oxygen content of the exhaust gases leaving the catalytic convertor.

If one or more of the oxygen sensors are faulty, your car may not pass the emissions test. If you drive your car with a faulty oxygen sensor, you may get poor gas mileage and it can damage the catalytic converter.

Oxygen Sensor-MATROX-1

Keep in mind:

  • Many oxygen sensors are damaged by leaking oil or coolant. If that is the case, the cause of that leak needs to be identified and repaired, or else the replacement oxygen sensor will be damaged as well.
  • New vehicles require specific oxygen sensors, and not the universal sensors that were common prior to 1996.

How it's done:

  • Scan the computer in the car for codes.
  • Inspect for vacuum leaks and holes in the exhaust system.
  • Remove and replace the oxygen sensor if it is bad.
  • Check electrical connections.
  • Check for proper operation of oxygen sensors.
  • Clear diagnostic codes.
  • Test drive car.

Our recommendation:

Keep up with the tune-ups. If check engine light is on, don't drive the car too long without getting it inspected. If check engine light is flashing, pull over and get the car towed to avoid costly repairs. Ask the mechanic to inspect the vacuum hoses and leaks in the exhaust system. If the vacuum hose or exhaust system is leaking, it will display an oxygen sensor fault code. Replacing an oxygen sensor may not fix the problem.

What common symptoms indicate you may need to replace the Oxygen Sensor?

  • Check Engine light is on.
  • Car is getting poor gas mileage.
  • Emission test fails.

How important is this service?

Your vehicle has multiple oxygen sensors, and they all help the car run optimally. The front sensors measure how much oxygen is in the exhaust stream to measure how rich or lean the gases leaving the gas chamber are. The rear sensors measure the oxygen content of the gases as they leave the catalytic converter. The oxygen sensors then relay this information to your vehicle’s electronic control unit, so that it can adjust as necessary. Because cars depend on an ideal fuel-to-air ratio to function optimally, the oxygen sensors are leaned on for engine performance. When your oxygen sensors fail your car will run less smoothly, get worse mileage, and have worse emissions.

Fast and easy Oxygen Sensor Replacement service at your home or office.

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Meet some of our expert Mercedes-Benz mechanics

Real customer reviews from Mercedes-Benz owners like you.

Dellano

14 years of experience
141 reviews
Dellano
14 years of experience
The service was completed satisfactorily in just about an hour with Dellano arriving just after 6 pm and completing the job before 7Pm. My only question is, "Is your hourly labor rate really $228/hour? Your site quotes $60-85/hour. Even if you add an hour for travel, my bill should only have been $120-!70 for labor at most What gives?"
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Junior

22 years of experience
53 reviews
Junior
22 years of experience
Junior provided great service!
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Ross

14 years of experience
41 reviews
Ross
14 years of experience
Ross was awesome! Called me from his cell to confirm appointment the night before. Showed up on time, even though I live deep in the woods. He showed me how to flush my brake lines, talked to me about other problems my car might have but without up-selling me on the work to be done. He performed a 1 hour job in 35 minutes, and he did it well. I have a notoriously difficult Mercedes model. Ross knew his way around it. MUCH better service than I have had at even Master Mechanics. I saved his number and WILL be booking him again. Also, I will be recommending to friends.
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Ruben

31 years of experience
31 reviews
Ruben
31 years of experience
Awesome !!!!!
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Get an instant quote for your car
Our mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing
Get a quote
CarServiceYourMechanic PriceShop/Dealer Price
1992 Mercedes-Benz 400SEV8-4.2LService typeOxygen Sensor - Front/Upper/Upstream ReplacementYourMechanic Price$446.58Shop/Dealer Price$566.14 - $867.63
1992 Mercedes-Benz 400SEV8-4.2LService typeOxygen Sensor - Rear/Lower/Downstream ReplacementYourMechanic Price$446.58Shop/Dealer Price$566.26 - $867.84
Show example Mercedes-Benz 400SE Oxygen Sensor Replacement prices

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