Question about 2005 Mercedes-Benz C-Class

1 Answer

2005 C240 Wagon Check engine light on

I started the car this morning and found the check engine light was on. Is it because I have used low grade petrol? Could I reverse the problem by using premium petrol again? I have check the car infro and no malfunction.

Posted by on


1 Answer

  • Level 2:

    An expert who has achieved level 2 by getting 100 points


    An expert that got 10 achievements.


    An expert that got 5 achievements.

    Vice President:

    An expert whose answer got voted for 100 times.

  • Expert
  • 203 Answers

The reason your light is on is because the system detected a problem related to the engine(emmissions system). Usually benz recommends premium grade fuel. It is possible that the plugs have fouled or some misfiring occurred and the system illuminated your light. Do you remember seeing the light flash at all before it remained constant. When the gas cap is left loose or the seal is worn out the M.E. module sets a p0440 codes(miner leak in evap) or a p0442(major leak in evap. The first thing I would check(assuming the car is running o.k.. is the gas cap tightness. Either way you will have to take the vehicle in and have the codes read and erased. If the module notices a problem during a key cycle within 17 minutes of vehicle operation it stores a fault. One the 2nd key cycle if the module notices the same problem with in 17 minutes it turns the light on. Hopefully I have been helpful

Posted on Jun 01, 2009


1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

A 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
The service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
Good luck!

Posted on Jan 02, 2017


Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

Check engine light

I would check my oil level again, if it is good, then maybe your oil pressure sensor is bad or loose at the connector. They may have forgot to tighten your drain plug securly.

Dec 12, 2013 | 2005 Buick LaCrosse

1 Answer

Envoy 2005 XL Cruise control not working

Your dealership should have seen any underlying codes. Most Cruise controls I've worked on are used on the vehicles vacuum. that is where i would start, because on a grade your engine uses more vacuum pressure thus taking from some where else.

Jan 12, 2012 | GMC Envoy Cars & Trucks

1 Answer

Check Engine light and TCS light will not go out vehicle chugged on acceleration this morning and now will not start

Insufficient information. Have the ECU (Engine Control Unit) scanned for any codes, then get back to me with any codes found stored in the ECU. We'll go from there.

Nov 25, 2010 | 2005 Hyundai Sonata

1 Answer

At red light engine seems like it wants to cut off.

try changing your pcv valve. if its dirty it may be causing the shuttering. as for the check engine light going on and off, you may have a bad gas cap. if the cap is faulty it will cause the engine light to come on at times because of a poor air to fuel ratio.

Mar 28, 2010 | 2000 Saturn SL

1 Answer

2003 Saab 9-5 CHECK ENGINE light with vibration

87 octane ,,,you kidding ---more like 95 octane .But this has nothing to do with the vibration and check engine light,forget having the codes read get the dealer to look at it

Nov 01, 2009 | Saab 9 5 Cars & Trucks

1 Answer

2005 Mercedes C240; looses power and check engine light comes

better to bring your car to dealer to avoid replacing part.,better to check air mass sensor or idling actuactor.

Feb 10, 2009 | 1995 Mercedes-Benz C-Class

1 Answer

C240 wagon (4-matic) idles low almost cutting out at stops

Hi,is never a bad thing to add a good fuel injector cleaner to your gas tank to prevent injectors from getting cloged ,you can try this for two days ,if no diference , check your air conditioner idle compensator,this regulates the idle when you turn the air on and off. good luck

Aug 18, 2008 | Mercedes-Benz C230 Cars & Trucks

1 Answer

Jerky engine

The easiest way is to check it at the fuel schrader valve mounted on the engine. Use a clear bottle and attach the fuel pressure gage. run the engine and release the fuel into a clean bottle. Any water and dirt will settle to the bottom of the bottle.

Jul 24, 2008 | 2005 Ford Club Wagon

Not finding what you are looking for?
2005 Mercedes-Benz C-Class Logo

433 people viewed this question

Ask a Question

Usually answered in minutes!

Top Mercedes-Benz Experts

Colin Stickland
Colin Stickland

Level 3 Expert

22326 Answers


Level 3 Expert

78919 Answers

Joseph Prosser

Level 3 Expert

772 Answers

Are you a Mercedes-Benz Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides