Check Engine Light Reset Attempt - 2014 Mercedes-Benz CLA250 Long-Term Road Test

2014 Mercedes-Benz CLA250 Long-Term Road Test

2014 Mercedes-Benz CLA250: Check Engine Light Reset Attempt

December 04, 2013

2014 Mercedes-Benz CLA250

A couple of days ago the Check Engine light winked on while another staffer was piloting our near-new 2014 Mercedes-Benz CLA 250. However, as is often the case, he couldn't correlate its arrival to anything special he was doing at the time. It did not come on during the startup sequence or while climbing a steep grade. He was just, you know, driving.

For its part, the car is fine. No hiccups, no reluctant acceleration, just the dang light on the dash. Well, maybe the fuel economy is a little underwhelming, but it's hard to be sure that's a thing with just 476 total miles on the clock.

I have a couple of low-cost OBD code scanners at home, so I hooked each of them up to see what they could tell me.

The first was the Scan Gauge II. It came back with a single diagnostic trouble code with an ominous-sounding title: P0004 - Fuel Volume Regulator Control Circuit High.

2014 Mercedes-Benz CLA250

Farther on in the definition, though, it points out that this code is "not common and sometimes is shown in error due to the design of the code reader." It goes on to say the first thing I should do is attempt to re-read the code with a higher-quality code reader.

Our CarMD is a fancier device, and it came back with a fancier code: P24D6. But this one is not defined on the common DTC-code websites except to say that it's an automaker-specific code. In other words, it's not one of the required OBD-II codes and I can't decode it without Mercedes equipment.

So I went back to the advice page for P0004: reset the Check Engine light and see if it comes back. That worked for the entire weekend, some 250 miles of unhurried driving, a typical mix of city and freeway errand-running and holiday shopping. "Must have been a fluke," I thought.

But then I started the engine in order to read the odometer mileage in preparation for writing this status update. Of course the light chose that moment to wink back on.

Enough messing around with toys. It's time for a dealer visit.

We're not the only ones. I've since learned that Mercedes CLA forums began lighting up in October with complaints from others about the P24D6 fault code. Like our car, their DTCs appeared in the first few hundred miles.

At first there was no remedy for what has been described as an OBD software glitch, but that changed in early November. Thing is, that's about the same time we took delivery of our car. We must have missed the fix by days, maybe hours.

We'll keep you posted once we schedule an appointment and bring it in. But at least it doesn't sound like a big deal, except for the hassle.

Dan Edmunds, Director of Vehicle Testing @ 715 miles


  • banhugh banhugh Posts:

    Let the hating begin!

  • exnevadan_ exnevadan_ Posts:

    more importantly, how's the convertible top holding up?

  • mercedesfan mercedesfan Posts:

    My wife's old R230 SL500 had a very similar issue early on. Turned out to be nothing and just required a software update, but a huge pain before it was diagnosed (CELs randomly every few days do not give a lot of confidence). Hopefully a similar update will remedy the CLA. I sure hope it doesn't end up having all the reliability issues our SL did in the long term. That would be very bad indeed for MB. Particularly since they have worked so hard to get their quality ratings back up in recent years.

  • noburgers noburgers Posts:

    Why do German cars have so many electrical issues, anyway?

  • quadricycle quadricycle Posts:

    @noburgers: Well reliability usually comes from simplicity and extensive testing. If you've got a luxury european car, complexity is usually higher, which along with that segment's focus on new, cutting edge (in automotive applications) technology will co

  • agentorange agentorange Posts:

    Just read some of the comment over on the CLA forum. What I don't get is why with all the testing the manufacturers do these days how 5-10% of a new model can display this behaviour. Strikes me that some of the testing is TOO controlled. Trust me, if you think American control freaks are bad, try working with one from Germany.

  • jerox jerox Posts:

    I have had the P24D6 error code two times on my 2014 B250 (same platform). I don't know if this can have an effect, but in both cases it was just after filling up tank with an unusual gas supplier: the first time at costco, the second time a small old-style countryside gas station.

  • casman6 casman6 Posts:

    Hello, my 2014 CLA250 just joined the check engine light club. I took it in on May 12th, and dealer called today to say they can not figure what the problem is. Vehicle not accepting the software and code updates. They said they are opening up a case file on the vehicle and consulting with the Main office for tech support. Hope everything will work out, we love our CLA250.

  • mdramesh mdramesh Posts:

    Hello, my 2014 CLA 250 also joined this club!!! Happened just yesterday, Jan 15. Called in the dealer (Natick, MA). Will keep you posted.

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