Q: Catalytic converter replacement.

asked by on January 11, 2016

The Check Engine light is on on my Mercedez-Benz. The car has less than 49,000 miles, but the dealership says I need to replace both the front right and left catalytic converters.

This would depend on the code that is retrieved from the check engine light. It never hurts to get a second opinion. I would recommend having another technician, such as one from YourMechanic, come to scan your vehicle for trouble codes. The diagnosis will be based on the codes that are present in the system. It is = possible that the oxygen sensors or the catalytic converter may need to be replaced.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

What others are asking

Car makes a loud sound every time I start my car, at idle, and when driving at low speeds

Hello. The first thing to check would be your fluid levels. I'm not sure what type of noise you have, but ticking noises at idle can be linked to a low oil level. If there is a vacuum leak, the...

My car doesn't move when in Drive or Reverse when idling

If you pushed the pistons into the calipers in order to accommodate the new pads, you may now have too much brake fluid in the reservoir. Check that the fluid level in the reservoir is not above the maximum level....

The rpm jumps up and down about 300 rpm when accelerator is constant. Only seems to happen when traveling between 40-50 mph

Hello, thank you for writing in. The truck may be having issues with air sensors, fuel pressure, or other electronic issues. I have have to replace the fuel module and the mass airflow on my 1998 S10 with 168,000 miles....

no crank no start

Check to be sure your immobilizer system (security) has not activated. If your fuel pump does not momentarily prime at key on and the starter circuit is dead as well, there is an electrical problem, possibly with the ignition switch,...

Severe grinding noise when accelerating on right side of front of vehicle. Video of wheel: https://youtu.be/nEgo_9Brw0c

Hi Chris. Thanks for contacting us and posting the video - it's a huge help. Here is the bad news you don't want to hear - it's likely a wheel bearing. They should be replaced in pairs, so you'll want...

How to remove headliner in '03 Cadillac CTS

Hi Andy. I believe we attempted to answer your question yesterday. Most people that have this problem will take their vehicles to a Cadillac dealership to have this completed. The main reason why we don't complete this service or provide...

My car won't crank or turn over to try to start. Maybe the Infiniti immobilizer security system.

To see if the Immobilizer System is not working properly or is active, check the security light on your vehicle. If the light is flashing fast, then the system is active. You can reset the system by removing the battery...

Car starts but won't catch until I press on the gas while starting

Hi Michelle. Thanks for contacting us today. Usually, this issue is caused by a faulty idle control valve or restriction of fuel flow through the throttle body. A damaged mass air flow sensor, dirty or clogged fuel filter, air filter,...

The engine started making noises and shakes

It depends, it could be something as simple as carbon deposits in the throttle body disrupting cold start airflow to low/unbalanced engine compression on a cold start. Because the engine is well-maintained, the first thing to do is to have...

Related articles

A Buyer’s Guide to the 2012 Mercedes-Benz E-Class
The The Mercedes-Benz E-Class is a midsize luxury vehicle that has been one of the most popular options for a number of years. The 2012 models, which now include a coupe, a wagon, and a convertible as well as the...
A Buyer’s Guide to the 2012 Mercedes-Benz SL-Class
Nothing Nothing says true sport luxury like a Mercedes hardtop convertible, and the SL more than delivers on the name’s promises. While both the SL and its sibling, the SLK, offer superior luxury, handling, and comfort, the SL boasts the...
Mercedes-Benz Certified Pre-Owned (CPO) Car Program
Shopping Shopping for a used Mercedes-Benz vehicle often leads many drivers to consider certified pre-owned options. Mercedes-Benz is one of many manufacturers that have a certified pre-owned (CPO) program. Each car manufacturer structures their CPO program differently; read on to...