Mercedes-Benz S420 Electronic Control Relay Replacement at your home or office.

Our mobile mechanics offer services 7 days a week. Upfront and transparent pricing.

Estimate price near me

Service Location

Customer Ratings

(13)

Included for free with this service

Online Booking

Mechanic comes to you

12-month / 12k-mile warranty

Free 50 point safety inspection

Our certified mobile mechanics can come to your home or office 7 days a week between 7 AM and 9 PM.

Customer Ratings

(13)

Electronic Control Relay Replacement Service

How much does a Electronic Control Relay Replacement cost?

On average, the cost for a Mercedes-Benz S420 Electronic Control Relay Replacement is $141 with $46 for parts and $95 for labor. Prices may vary depending on your location.

CarServiceEstimateShop/Dealer Price
1996 Mercedes-Benz S420V8-4.2LService typeElectronic Control Relay ReplacementEstimate$207.35Shop/Dealer Price$247.94 - $330.34
1994 Mercedes-Benz S420V8-4.2LService typeElectronic Control Relay ReplacementEstimate$187.35Shop/Dealer Price$227.97 - $310.39
1998 Mercedes-Benz S420V8-4.2LService typeElectronic Control Relay ReplacementEstimate$187.35Shop/Dealer Price$227.97 - $310.39
1997 Mercedes-Benz S420V8-4.2LService typeElectronic Control Relay ReplacementEstimate$187.35Shop/Dealer Price$227.93 - $310.32
1995 Mercedes-Benz S420V8-4.2LService typeElectronic Control Relay ReplacementEstimate$187.35Shop/Dealer Price$228.00 - $310.44
1999 Mercedes-Benz S420V8-4.2LService typeElectronic Control Relay ReplacementEstimate$187.35Shop/Dealer Price$227.97 - $310.39
Show example Mercedes-Benz S420 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.

Fast and easy service at your home or office

Backed by 12-month, 12.000-mile guarantee


Meet some of our expert Mercedes-Benz mechanics

Real customer reviews from Mercedes-Benz owners like you.

Excellent Rating

(13)

Rating Summary
12
0
1
0
0
12
0
1
0
0

Eric

15 years of experience
134 reviews
Eric
15 years of experience
Mercedes-Benz S420 V8-4.2L - Oil Change - Bowie, Maryland
Kept me informed for his arrival. Was very friendly.

Kenneth

20 years of experience
801 reviews
Kenneth
20 years of experience
Mercedes-Benz S420 V8-4.2L - Oil Change - Los Angeles, California
He is the real deal... On time, did great work, very all together" good man and mechanic...... Thanks Kenneth.

Manuel

12 years of experience
98 reviews
Manuel
12 years of experience
Mercedes-Benz S420 V8-4.2L - Car is overheating - Naples, Florida
Very prom and good mechanic .

Whitney

39 years of experience
783 reviews
Whitney
39 years of experience
Mercedes-Benz S420 V8-4.2L - Fix a Flat Tire (Plug Holes) - Palo Alto, California
It's great.

Excellent Rating

(13)

Rating Summary
12
0
1
0
0
12
0
1
0
0
Number of Mercedes-Benz S420 services completed
143+
services done by our mechanics
TOTAL NUMBER OF EXPERT Mercedes-Benz MECHANICS
1100+
experts on our platform

Recent articles & questions

Veteran and Military Driver Laws and Benefits in Minnesota
The The state of Minnesota offers a number of benefits and perks for those Americans who have either served in an Armed Forces branch in the past, or are current active military members. Disabled veteran registration fee waiver Disabled veterans...
P2517 OBD-II Trouble Code: A/C Refrigerant Press Sensor B Circuit Low
P2517 code means the A/C refrigerant pressure sensor is out of the normal refrigerant level range, a faulty switch, wiring, or connectors.
How to Replace a Pinion Seal
A pinion seal keeps oil in the differential and keeps water, dirt, and debris out. A failing pinion seal will leak which can ruin the differential.

The headlights malfunction

The bulbs are xenon type bulbs and they will fade away before they burn out. My suggestion would be to replace both headlight bulbs (https://www.yourmechanic.com/services/headlight-bulb-replacement). This way you do not change one and the other burns out in a few...

Do you need to change the rotor when the brake pads needs to be replaced for the front and rear?

Hello. Thanks for writing in about your Mercedes-Benz ML350. It is recommended to replace it if the rotor surface is worn, damaged, or is too thin. Typically I would always recommend replacing the rotors anytime the pads are changed. By...

1997 Toyota Tercel brake lights , radio , clock, temp gauge all stopped working - head lights work and speedometer work - engine s

It is possible that your alternator could be failing. When an alternator fails, it can cause other electroncis on the vehicle to malfunction. I would recommend starting by checking the charge output of the alternator using a digital multimeter. If...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (844) 997-3624 · hi@yourmechanic.com