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Mercedes-Benz CLS500 Rear Oxygen Sensor Replacement

An oxygen sensor replacement is usually a pretty straightforward and affordable task. We stress the term usually because replacement cost can vary, depending on what type of car you have.

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Average Shop Price $428
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This range covers an average Rear Oxygen Sensor replacement. Tell us your car to get a guaranteed price from RepairSmith.

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Mercedes-Benz CLS500 Rear Oxygen Sensor Replacement

RepairSmith offers upfront and competitive pricing. The average cost for Mercedes-Benz CLS500 Rear Oxygen Sensor Replacement is $234. Drop it off at our shop and pick it up a few hours later, or save time and have our Delivery mechanics come to you.

Car
Location
Quoted on
Price
2006 Mercedes-Benz CLS500
5.0L V8 Base • 99,000 miles
Rancho Cordova CA 95670
Nov 16, 2020
$207 - $253
2006 Mercedes-Benz CLS500
5.0L V8 Base • 217,000 miles
Lafayette CA 94549
Nov 15, 2020
$194 - $237
2006 Mercedes-Benz CLS500
5.0L V8 Base • 19,000 miles
Long Beach CA 90813
Oct 26, 2020
$234 - $286
2006 Mercedes-Benz CLS500
5.0L V8 Base • 197,000 miles
Salinas CA 93905
Oct 20, 2020
$230 - $281
2006 Mercedes-Benz CLS500
5.0L V8 Base • 30,000 miles
Rancho Cucamonga CA 91739
Oct 18, 2020
$224 - $274
2006 Mercedes-Benz CLS500
5.0L V8 Base • 66,000 miles
Fresno CA 93710
Oct 7, 2020
$194 - $238
2006 Mercedes-Benz CLS500
5.0L V8 Base • 81,000 miles
Rancho Cucamonga CA 91739
Oct 1, 2020
$201 - $245
2006 Mercedes-Benz CLS500
5.0L V8 Base • 141,000 miles
Sacramento CA 95831
Sep 19, 2020
$201 - $245
2006 Mercedes-Benz CLS500
5.0L V8 Base • 174,000 miles
Castro Valley CA 94546
Sep 18, 2020
$217 - $265
2006 Mercedes-Benz CLS500
5.0L V8 Base • 201,000 miles
Lynwood CA 90262
Sep 17, 2020
$204 - $250
Last Updated:
Dec 17, 2020 6:25 PM
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What is a Rear Oxygen Sensor?

This might blow your mind but…oxygen sensors (O2s) are sensors that measure oxygen. Yep, the sensors calculate the amount of oxygen in the exhaust stream, then share that information with your car’s main computer. Most modern cars have at least two oxygen sensors: one before the catalytic converter and one after the catalytic converter. In case you were wondering, the catalytic converter, which is located in the exhaust system, is an emissions control device that cleans up the fumes leaving your engine. Anyhow, the front oxygen sensor (also known as an upstream oxygen sensor) is a key input to your car’s computer for fuel control. The computer uses information from the sensor to estimate the engine’s air-fuel mixture. Then, it adjusts fuel delivery accordingly. On the other hand, the rear oxygen sensor (also known as a downstream oxygen sensor) primarily monitors the performance of the catalytic converter. The rear sensor has very little, if any, input regarding fuel control. Oh, and one more thing – most modern oxygen sensors have built-in heaters. When you first start your engine when it’s cold, the heater element gets the sensor nice and toasty. That allows the sensor to get up-to-speed and begin operating more quickly.

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Symptoms of a failing Rear Oxygen Sensor

Check engine light

If your car’s rear oxygen sensor isn’t doing its job, chances are, the computer will notice and turn on the check engine light. The device will also store corresponding diagnostic trouble codes (DTCs) in its brain. Your mechanic can retrieve said codes using an electronic device, called a scan tool.

Failed emissions test

Is it time for your routine emissions test? Well, guess what – you’re not going to pass if the check engine light is on from a bad rear oxygen sensor. You also won’t pass if the rear oxygen sensor is out to lunch and it’s preventing your car’s computer from running its system self-tests.

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How urgent is a Rear Oxygen Sensor Replacement?

The rear oxygen sensor is less of a troublemaker than the front oxygen sensor. For the most part, the rear oxygen sensor just polices the catalytic converter. So, it’s unlikely to leave you stranded and it shouldn’t cause any additional harm to your vehicle.

But it will keep that annoying check engine light illuminated and, really, do you want to look at that thing every day? Plus, a bad rear oxygen sensor can cause you to fail a state emissions test – and nobody wants that.

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