I just got my car back a few days ago from the motor mounts being replaced. It has been running smooth and quiet as ever. Yesterday I had to take the car back to the dealer because the steering wheel was a little crooked, due to not being set straight during the motor mount job.

Go to dinner with the wife tonight, come out, start the car, and the check engine light is on. I get to a stop sign and pull out my phone with the torque app to read the codes. It came up with the following:

1. P0300 Random/Multiple cylinder misfire
2. P0308 Cylinder 8 misfire
3. P2043 Reductant temperature Sensor Circuit Range/Performance
4. P204e Reductant pressure sensor circuit intermittent/erratic
5. P20f3 SCR NOx Pre-catalyst efficiency below threshold

These are the generic codes from the Torque app. STAR may find more. I find all of this odd since the car is running beautifully (for the moment) and I cannot detect any misfires or hear anything out of the ordinary. Is it possible the mechanic left something loose when he changed out the motor mounts? The car was in a couple of weeks ago for another check engine light and they had to reconnect and tighten a vacuum hose by the engine intake. When I had it in earlier in the week for the engine mounts, no codes were coming up. I just find this strange that this happens all of a sudden a couple of days and only a few engine cycles after the car was in the shop.

Any ideas on what may be throwing the codes? Bad coil pack? Bad or loose ECU? Catalytic issues?

 

That sucks. Those mechanics are hacks. Fortunately though, you have a warranty.


So really, your just out lost time and some frustration.

 

Sorry to hear about these codes and your drama not being solved yet .
First two codes aren't new to me , in my older cars I had same codes which turned out to be to do with a bad ignition system and we had to replace ignition coil as well as spark plugs and wires .

The last 3 codes from bottom are the ones which I didn't know existed

 

Sound to me like you have a bad coil pack. Or they didn't disconnect your wiring before replacing the motor mounts and damaged the harness. Check to see if any of the wires are pinched, damaged or cut.

 

Ask them to make sure the ignition controller plugs are firmly in place. They messed up something on the harness side.

 

Not sure yet. I dropped off the car at the dealer yesterday. I called my service adviser in the morning and he mentioned that the misfire codes could have had to do with still using the winter blend of fuel and having warmer weather as of late. He said the V12's are extremely sensitive. He told me to clear the codes then see if they re-appear. I cleared them, took the car for a spin....and about 1.5 miles into the drive, I nailed the throttle and the check engine light started flashing and the car went into limp mode. I pulled over, tried to pull up the codes, but no codes showed up on my Torque app. I shut down the car, restarted it, and it was fine again.

I then called my adviser and he said to bring it in if I felt confident in driving it the 20 miles or so to the dealership. I cleared the check engine light and it drove fine, but I didn't nail the throttle on the drive. When I was less than a mile from the dealership, I decided to give a hard stab at the throttle, and immediately the check engine light came on and I could feel it misfiring. No codes came up on my torque app again. I gave them the 5 codes from the other night and they will go into it tomorrow. They think it's definitely an ignition issue that could be a coil pack on 1 bank, or perhaps an ignition module.

What is disconcerting is that the car was running beautifully for a couple of days after the motor mounts were replaced, then all of a sudden this. My car received the 40k mile service at 21k miles, which was the biggie that included a change of all spark plugs. They said that if it turns out to be a coil pack, they will have to change the plugs on that bank again, even though they only have 12k miles. The coil pack would be covered by my warranty, but likely not the plugs.

After what I've described, does this still sound like something they did while replacing the motor mounts? It only has the issue when the peddle is pushed all the way to the floor....although the other night the check engine light came on right after starting the car.

 

Good luck with your repair

 

I wonder if Mercedes Service centers pull these shenanigans to pump up profits while charging the warranty companies. Thoughts?

 

I'm not tearing down my engine. I don't even know what's wrong with it yet. This isn't some simple Honda. It's a complicated V12. I'm sure STAR will find the faults and I'm more than happy to let the dealer handle it, even if I'm stuck paying for plugs. I don't think there's a MB dealer in the country that would let you buy your own parts, and they install them. I don't know of any reputable indy shops who can service a car like the 600 that would do that either. They know this happened only days after the mounts were installed. It could just be a coincidence, or it could have happened from something they did while installing the mounts. They've been very good to me and have worked well with my warranty company in getting all claims paid, so I'm not going to rock this boat. This is one of the biggest and well known dealerships in the Chicago area, as they deal and service MB, BMW, Porsche, and Cadillac and have been around for 40 years in a very expensive suburb.

Very doubtful. And certainly not this dealership.

 

It is prolly a coil if it fails under load. Common. Lol @ replacing plugs when replacing a coil. Certainly no need.

 

Good to know. So a bad coil won't foul the plugs beneath it?

If that's the case, I'll probably shut down the replacement of the plugs if it does end up being a coil pack.

 

Agree. Once you're looking at three times the amount of warranty claims relative to the premium it's a good idea to lay low and let the process work. Plugs are a small price to pay.

My 220 needed a rear diff at 70k miles for bearing noise. I told the warranty company an LKQ pumpkin under 50k miles was fine, not reasonable I felt to demand a $3500 unit.

Like my CPA always says: Pigs get fat. Hogs get slaughtered.

 

I took that in a few different ways.
1. Pigs are colored and hogs are pink. Meaning whitey will die?
2. Pigs don't have quite the fatty layer, so they have to grow. Thus are not IRS targets.
3. Hogs are domestic and thus are made for human consumption.

 

What my CPA means is that if you maybe get a little creative with deductions like a pig you're unlikely to get murdered in an audit, whereas if you get greedy like a hog you're likely to get butchered.

I'm too lazy and not creative enough to mess with hiding income. I just pay what I owe.

 

Oh! I see. I have read much of the irs law on IRS.gov to learn ways to get all I can during tax season.

 

Why would that be? I've replaced 4 sets in two v12s I've owned. Always replaced the plugs - they are so cheap, and you are already paying labor. No? Wouldn't they fail at similar intervals?

Thanks,
Erik

 

The plugs only have 12k miles on them. If a bad coil(s) didn't cause damage to the plugs, why have them replaced so soon? And it would likely only be on 1 bank.

 

$1900+ later, 1 coil pack bank replaced and car is running great again. Only the deductible to me. Adviser said that when one pack goes out on the V12 motor, the other bank is almost sure to follow in short order. I'll be looking forward to more CE lights in the near future.

I think it might be time to have a running total of all repairs covered by my warranty, so that current and future members can see the importance of having a warranty on their cars. If others are interested, I'll start digging up my receipts and make a separate thread, and will update as more repairs are done.

 

Yes. Once one side is gone the other one follows shortly after

 

Nice! For me, even with the warranty, when the thing starts acting up and it's in the shop a bunch of times I lose interest and want it gone. Then again, I usually don't start out with 24k miles. With yours, it's probably just that point in its life cycle where it'll need a bunch of stuff all at once and then be fine for another 30k.

Definitely do that warranty thread and running total of premium and deductibles paid vs repair costs. I'll add to it with the CPO numbers on mine.

 

DaveW68,What year is your S600 and how many miles?

 

2007, currently at 33k miles.

 

They have had a revision since the originals. The new one should last quite a while.

 

Interestingly, I just checked my service records and both coil packs were replaced around 8k miles. And yes, the part number is different on the new coil compared to those put on at 8k miles.

 

Yes, they knew it was a defective part and still sold them. The revised one will last you for a very long time! For example, the one they replaced on my 06 was the revision and never had a minutes trouble. Also, I say a 2012 CL 600 with 98K miles at auction and had never been to the dealer except for services. That tells you how much more devoted to quality they had put into making the revised models.