Engine light repairs

My car has 140K miles on it, 2005 model, runs great. I brought it in for full service with spark plug replacement etc. Dealer shop finished service and I drove off. A week later check engine light comes on. Car still runs fine. I bring it to the dealer shop and ask him to shut it off. Now the workshop tells me that there are 2 issues that is causing engine light. 1. ESG valve is not functioning right and needs replacement for $1400. 2. Fuel Evap system solenoid (canister purge solenoid) is not functioning right and needs replacement $450. For a total of $1800 valve and solenoid replacement will shut the light off. What are my options here? 1. I think the dealer shop is responsible for letting me drive off after full service. what if they had done some thing wrong to set the lights on. 2. How do I beleive this given they can tell me anything they want since its in shop and I have a MB rental. 3. What if I drive with light on since its driving fine and if it breaks down - we fix it then. I dont know why I should put in another 1800 after a full service for $2000. Its running fine and not worth more than 5 - 7K. What do I do?? what are my options?

Some auto parts stores will plug a code reader into your vehicle and provide the code(s) that caused the Check Engine light to turn on.

Until that’s done, don’t assume the previous maintenance caused the Check Engine light to come on.


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As Tester noted, you can have the codes read, usually for free, at an auto parts store, then post the code number here. Then we may be able to give you some ideas.

Or, go to an independent shop, not a chain likePep Boys or Firestone, for a second opinion and estimate. Likely you will be charged another diagnosis fee, shop might waive the fee if they do the repairs.

My guess these issues are not related to service performed at your MB dealership. On a 17 year old vehicle, anything can happen.

Bottom line, yes it is frustrating to require more repairs, but needs to be done.


Issues can start after a shop visit and not be caused by the shop. You will probably never know. I agree with the others, get a second opinion. If you get the OBD-II codes read, get a printout or take a photo of the code reader screen and tell us what the codes are. Maybe we can help you figure it out.


don’t be afraid to get a second opinion. You obviously do not trust this dealership, so find someone you do trust.

along those lines: you said you got a full service done for $2,000
What all was done for that 2 grand? You said plugs, but what else? without knowing everything that was done, and without what the actual current codes are- we can only guess.

you won’t find many folks here that will suggest you keep driving the car with the check engine light on. Driving it with the check engine light on could make repairs later much more expensive, could cause you to fail safety/emissions inspections, and will cause your vehicle to emit excessive harmful emissions into the atmosphere than it should.

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Do you mean the EGR valve? If so, and you defer replacing it now, your car may not pass emissions testing. Same goes for the purge valve.

While the shop could have inadvertently damaged the engine and causing these problems while doing the other stuff, you offer no proof this happened, and it seems very unlikely. EGR and Purge valves are common replacement items on older cars, you can see for yourself what other posters here have said about these valves on their cars using the forum search feature, upper right this page.

Suggest to simply accept it is what it is, new problems are unrelated and a coincidence, and schedule your shop to fix the remaining problems for you. Remember your car is 17 years old. The best way to avoid having to deal w/ this sort of frustration is to trade it in on a new Mercedes. BTW, some newer cars don’t even use EGR valves.

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Its the EGR valve. yest. All of the counsel I am seeing so far has been very helpful. I called the service manager at the dealershop and had a talk. I told him I believe the validity of the codes but coming so close to a full service and a big budget item asked him to verify. He agreed that its best that its verified. So he is asking the mechanic to set the engine light back to normal and take the car for a 10 mile spin and then if the lights come back on lets get the repairs done. He did indicate that its only going to affect emissions testing

Full service meant all filters, fluids, plys sparkplugs and wires. The sparkplus and wires alone is 1200 something

I think that what you are learning is that every time you go to the dealer for service, you should just take a large wad of cash, then hand it to the service advisor, saying “call me when it is fixed”. A Mercedes is not a car that the owner should be asking “why”. Remember, that is also an important part of the whole show of status.


Reminds me of the time back around 2008 when gas prices were also high, I was walking past a neighbor’s house, he had his motor home parked in front, boat behind, says he’s getting ready to go camping. I’m thinking he should just hand his credit card over to the gasoline companies and be done w/it … lol …

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True but whats your answer to high gas prices - buying an EV Tesla. I am still not ready to give up on my E500 4 matic. Plenty of power and love driving it more than a Tesla model 6.

I would get away from that dealer . If it is a 2005 model with the 4 cylinder then both of those parts are less than $50 a piece on rock auto . Check with friends for a good independant mechanic , he will charge for diagnosis thats only fair but $1800 for those two parts sounds waaaaaaay out of line even if they have to dissassemble stuff to get at them .

A 2005 E500 will have a V-8, not a 4-cylinder

And a good independent shop’s hourly rate will be close to the dealership’s hourly rate

Where you might save money is with aftermarket parts, but the price won’t be cut in half

You are asking about what to do about high fuel prices and you have a vehicle that is rated at 16mpg combined ? I guess find a independent shop and have this fixed and then practice Hypermiling or trade for something more fuel efficient.

It’s going to take a little more than that

The car needs to operated in the proper way, so that the readiness monitor runs to completion

Then even if the mil isn’t back on, the mode 6 data can be checked, to see just how badly it failed or passed

Sometimes a 10 mile road trip isn’t sufficient

The danger is that if you don’t drive the car enough for the monitor to run to completion, but the mil isn’t yet on, you can convince yourself everything is okay, hand the car back to the customer, only to have the mil come on a few days later and now the customer’s quite upset


Sounds like a great car. Many people here are afraid to spend and money on auto repair, easier to replace the car.

Once a month I see a customer spending $8,000 to $10,000 on a vehicle your age. Shocking to those who are poor but if you walk to the showroom and look at comparable vehicles, (not Hyundai Accent) the cost of keeping the car another 5 years is less that the depreciation of a new car on the first day.

He was responding the George’s off-topic comment about his neighbor’s RV, let’s focus on the topic.

I dont have an update yet from the shop and I am holding on to a MB rental a brand new E350 with only 1000 on odometer. They have had the whole weekend to test.

Its not a 4 cylinder , dont know where that came from. Its a 8 cylinder motor with 2 plugs a cylinder. I agree that the parts price seems out of whack but the breakdown may include labor plus part. I have to figure out what the real charge is . The way it works is - he will give mean estimate and then apply a 25% discount. It still is crazy that MB shop in CA charges 130 - 150 for labor

Why is that crazy? That’s roughly the going rate for most shops here in southern NJ, not necessarily MB.

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A 130 to 150 per flat rate hour may sound high off the cuff but when broken down it is not that much. If you were to sit down and see that pie sliced up then it would not seem as high.

My primary care doctor sees me for approx. 3 minutes on a Level I visit. For this he bills 156 dollars to put it into perspective.
If I have a 10 A.M. appointment he’s already seen 30 or more patients and no one gets a free or discounted pass.

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