Mercedes-Benz C300 Electronic Control Relay Replacement at your home or office.

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Electronic Control Relay Replacement Service

How much does a Electronic Control Relay Replacement cost?

On average, the cost for a Mercedes-Benz C300 Electronic Control Relay Replacement is $141 with $46 for parts and $95 for labor. Prices may vary depending on your location.

CarServiceEstimateShop/Dealer Price
2014 Mercedes-Benz C300V6-3.5LService typeElectronic Control Relay ReplacementEstimate$207.35Shop/Dealer Price$247.94 - $330.34
2016 Mercedes-Benz C300L4-2.0L TurboService typeElectronic Control Relay ReplacementEstimate$187.35Shop/Dealer Price$227.97 - $310.39
2015 Mercedes-Benz C300L4-2.0L TurboService typeElectronic Control Relay ReplacementEstimate$187.35Shop/Dealer Price$227.97 - $310.39
2019 Mercedes-Benz C300L4-2.0L TurboService typeElectronic Control Relay ReplacementEstimate$187.35Shop/Dealer Price$220.44 - $297.20
2009 Mercedes-Benz C300V6-3.0LService typeElectronic Control Relay ReplacementEstimate$187.35Shop/Dealer Price$228.00 - $310.44
2008 Mercedes-Benz C300V6-3.0LService typeElectronic Control Relay ReplacementEstimate$187.35Shop/Dealer Price$227.97 - $310.39
2010 Mercedes-Benz C300V6-3.0LService typeElectronic Control Relay ReplacementEstimate$192.35Shop/Dealer Price$232.73 - $314.97
2018 Mercedes-Benz C300L4-2.0L TurboService typeElectronic Control Relay ReplacementEstimate$192.35Shop/Dealer Price$225.69 - $302.66
Show example Mercedes-Benz C300 Electronic Control Relay Replacement prices

What is the Electronic Control Relay all about?

A wide range of electronic systems must work properly in order for the vehicle to operate. That means there is a need for several different controllers to ensure proper operation. One of the most important is the electronic control relay. You might be more familiar with the term “main relay” because of its role in vehicle performance.

The electronic control relay operates the fuel pump and sends power to the engine’s injectors. Without the main relay, fuel will not flow from the tank to the engine, and your injectors will not atomize gasoline into the combustion chamber. In short, your car wouldn’t run. Electronic control relays are subject to failure from a number of different problems, including outright failure, heat damage, cracked solder and more.

Keep in mind:

  • The electronic control relay may not operate, or may operate intermittently depending on the source of the trouble.
  • A number of other problems can masquerade as a main relay failure, so it’s vital that you have one of our expert mechanics diagnose the issue.

How it's done:

  • The electronic control relay is located and accessed then verified it needs replaced
  • The defective relay is removed from the vehicle
  • The new electronic relay is installed
  • The components that the electronic relay operates are checked for proper operation
  • The vehicle is road tested for proper operation

Our recommendation:

Traditional turnkey ignition the relay will click three times during the starting process. If you listen closely, you should hear a single click when you turn the ignition to “on”. You should hear another when the Check Engine light turns off. Finally, there should be a third click when you turn the key to the “start” position. If you do not hear a click at any of these three points, there may be a problem with the electronic control relay. Have one of our expert mechanics diagnose and replace the relay if required.

What common symptoms indicate you may need to replace the Electronic Control Relay?

  • Engine doesn’t start, especially in cold weather
  • Engine may not start a few minutes after turning it off
  • No sound from the fuel pump when the ignition key is turned to “On”

How important is this service?

Given the fact that the electronic control relay powers the fuel pump and your fuel injectors, it is essential to replace a faulty one. However, many other problems can present similar symptoms, so it’s very important to have the issue diagnosed by one of our expert mechanics.

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Meet some of our expert Mercedes-Benz mechanics

Real customer reviews from Mercedes-Benz owners like you.

Excellent Rating

(508)

Rating Summary
481
15
5
1
6
481
15
5
1
6

Jason

9 years of experience
175 reviews
Jason
9 years of experience
Mercedes-Benz C300 V6-3.0L - Oil Change - Redwood City, California
2nd time we've booked an appointment with Jason. He's on time and did a good job servicing our vehicle. Highly recommended!

Juan

9 years of experience
323 reviews
Juan
9 years of experience
Mercedes-Benz C300 V6-3.0L - Check Engine Light is on - Oviedo, Florida
Juan is the most knowledgeable mechanic I've ever met- he really cares about his work. Highly recommended!

Kenneth

20 years of experience
792 reviews
Kenneth
20 years of experience
Mercedes-Benz C300 V6-3.0L - Serpentine/Drive Belt - Los Angeles, California
Very knowledgeable, outstanding and most importantly very patient He takes things very easy and made me feel like l have known him for years. A very humble person. Strongly recommended. Thank you Kenneth and Thank you yourmechanic for sending me a good person.

Brock

32 years of experience
49 reviews
Brock
32 years of experience
Mercedes-Benz C300 V6-3.0L - Car is making a noise - San Jose, California
Professional, extremely knowledgeable, and friendly. Took time to explain everything thoroughly and used analogies I could understand since I am not mechanical. I respect his opinions and evaluations and feel he is the very best! Much appreciated to have him evaluate the rubbing noise sound in my 2009 Mercedes 300C. I was delightfully impressed, thank you Brock!

Excellent Rating

(508)

Rating Summary
481
15
5
1
6
481
15
5
1
6
Number of Mercedes-Benz C300 services completed
5588+
services done by our mechanics
TOTAL NUMBER OF EXPERT Mercedes-Benz MECHANICS
1100+
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