BMW 645Ci Oxygen Sensor Replacement at your home or office.

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Oxygen Sensor Replacement Estimate for BMW 645Ci

BMW 645Ci Oxygen Sensor Replacement costs $295 on average. Following is a breakdown of the labor and parts estimates.

YourMechanic Price
$278 to $325
Labor: $98 -$112
Parts: $180 -$213
Average Dealer price
$489 to 557
Average Shop price
$341 to 383
Get an instant quote for your car
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
2005 BMW 645CiV8-4.4LService typeOxygen Sensor - Rear/Lower/Downstream ReplacementYourMechanic Price$457.02Shop/Dealer Price$582.35 - $878.29
2004 BMW 645CiV8-4.4LService typeOxygen Sensor - Rear/Lower/Downstream ReplacementYourMechanic Price$457.02Shop/Dealer Price$582.52 - $878.59
2004 BMW 645CiV8-4.4LService typeOxygen Sensor - Front/Upper/Upstream ReplacementYourMechanic Price$524.66Shop/Dealer Price$666.96 - $1013.68
2005 BMW 645CiV8-4.4LService typeOxygen Sensor - Front/Upper/Upstream ReplacementYourMechanic Price$524.66Shop/Dealer Price$667.01 - $1013.77
Show example BMW 645Ci 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 BMW mechanics

Real customer reviews from BMW owners like you.

369 reviews
Patrick
28 years of experience
He seems professional. I paid for the lights to be addressed and they are all still on including a low engine oil light. He said he would return to check it out further after his next appointment but I did not hear back from him. I was told by BMW that the power steering fluid needs to be drained, flushed and refilled. He sucked it out with a hose twice and this will not ensure that the oil that was accidentally placed in there would be completely removed. I am no mechanic but I am going off of what BMW told me. I wanted to get a lot more work done. I want all the lights to be addressed and fixed so I started with the check engine lights to be looked at and not just reset. I want everything to be fixed. Thank you
2005 BMW 645CI - OIL CHANGE
194 reviews
Emmette
32 years of experience
Emmette did the starter and manifold gasket on my 2004 BMW. He did a great job in spite of the heat.
2004 BMW 330I - CAR STARTER REPAIR
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Jonathan
13 years of experience
Quick, professional, thorough pre-purchase inspection.
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Clarissa
23 years of experience
Very happy. I booked a ball joint replacement that a tire store told me I needed. Clarissa checked and that was not really what the car needed; it needed a control arm bushing instead. I appreciate the honesty and saving me from work I did not need. Clarissa was easy to talk to and work with.
1996 BMW 318I - CAMSHAFT POSITION SENSOR REPLACEMENT
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
2005 BMW 645CiV8-4.4LService typeOxygen Sensor - Rear/Lower/Downstream ReplacementYourMechanic Price$457.02Shop/Dealer Price$582.35 - $878.29
2004 BMW 645CiV8-4.4LService typeOxygen Sensor - Rear/Lower/Downstream ReplacementYourMechanic Price$457.02Shop/Dealer Price$582.52 - $878.59
2004 BMW 645CiV8-4.4LService typeOxygen Sensor - Front/Upper/Upstream ReplacementYourMechanic Price$524.66Shop/Dealer Price$666.96 - $1013.68
2005 BMW 645CiV8-4.4LService typeOxygen Sensor - Front/Upper/Upstream ReplacementYourMechanic Price$524.66Shop/Dealer Price$667.01 - $1013.77
Show example BMW 645Ci Oxygen Sensor Replacement prices

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