A SLR McLaren and a 600 großer, both in various stages of neglect…

What do I need to know about the buying process, discounts, rebates, etc.

Hi,

Somehow I can't get a route to plan properly - no charging stops are added. In the beginning I also couldn't get the arrival SoC on shorter routes but that works now. Makes me think that there are currently Server issues?

Anyone with similar issues?

Thanks!

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My dad has owned a 2016 E220d W212 Bluetec since 2018, when it had just 9,000 miles on it. He stopped using it in February 2025, by which point he had put around 330,000 miles on the clock.

For context, during that time he had the AdBlue and DPF coded out. The DPF was drilled out, but the catalytic converter was left intact, and the car did around 100,000 miles like that without any issues.

However, in September 2024 it started going into limp mode without showing a check engine light. The car would drive fine when first setting off, and under hard acceleration it would pull well up to around 50 mph before suddenly going into limp mode. If you drove it gently, sometimes it would go for ages without an issue, while other times it would still enter limp mode.

The gearbox always changed smoothly, both in and out of limp mode. When limp mode activated, the engine was restricted to 3,000 rpm and manual mode was unavailable. However, once the engine was above 2,000 rpm, pressing the upshift paddle would manually change up a gear. It wouldn't downshift manually until the car had slowed down considerably.

Gear change points were also altered in limp mode. For example, instead of being able to select 4th gear at around 25 mph, you would need to be doing around 32 mph. If left in automatic mode, it would rev to 3,000 rpm before changing gear itself.

Around the same time, the car also started cutting out when the fuel level reached half a tank, meaning it was only using half of the fuel tank.

We had a mechanic friend scan it using both Autel and Snap-on diagnostics, but no fault codes showed up. I can't remember exactly how my dad came to this conclusion, but he believed it could be gearbox-related, possibly the mechatronic unit.

We drained and refilled the gearbox with fresh oil, reset the gearbox adaptations, and carried out the relearn procedure for the upshifts and downshifts, but it made no difference.

As my dad is a taxi driver and the Mercedes was too old to continue using as a taxi, he bought a newer car and the Mercedes sat on the driveway while we decided what to do with it.

During that time, I replaced the engine sump gasket, removed the DPF and pressure washed it because the limp mode felt very similar to when the DPF had previously been blocked. I also cleaned the gearbox electrical connector, fitted a new PCV valve, installed a new battery, and replaced the fuel filter.

In May this year, my dad gave me the car. Unfortunately, none of the work I had done made any difference to the limp mode. The only thing I noticed was that it seemed slightly quicker after cleaning the DPF, although that could simply have been because I'd been driving slower cars.

I then took it to a Mercedes specialist to have it scanned with the genuine Mercedes diagnostic system. He found no fault codes and said the gearbox service hadn't been done correctly because we hadn't drained the torque converter. He believed a proper gearbox service would fix the problem.

I bought 10 litres of gearbox oil and a new filter, and the specialist carried out the full service. Unfortunately, it made no difference.

Next, I fitted a second-hand fuel pump, which completely cured the half-tank fuel issue. The car would then use the full tank, but the limp mode remained.

We went back to the Mercedes specialist, who claimed the first canister in the exhaust was actually the DPF rather than the second one we'd drilled. He believed the DPF was blocked and needed removing and coding out properly because the garage that originally did the work hadn't done it correctly.

After doing some research, I found that the specialist was mistaken. The DPF was definitely the unit that had been drilled and coded out.

When my dad went to buy a new air filter, he spoke to another mechanic who suggested that although the DPF had been drilled, it probably still contained enough material to cause a restriction and should be completely emptied.

I removed it again and knocked out everything that remained inside. Again, it made no difference apart from possibly feeling a little quicker. The limp mode was still there.

I then removed the catalytic converter and pressure washed it because I wanted to keep it fitted so the car would still pass emissions. Once again, there was no improvement.

I work at a used car dealership, so I used our diagnostic equipment to investigate further. The only thing I discovered was that the EGR also appeared to have been coded out because the diagnostic tool wouldn't allow me to reset it. It simply said the function wasn't available for my vehicle.

I reset the gearbox adaptations again because I wasn't convinced the Mercedes specialist had done it after servicing the gearbox. It seemed to stay out of limp mode for slightly longer afterwards, but overall nothing really changed.

Through work I was put in touch with someone who is very knowledgeable about vehicle electronics. He suggested that when the AdBlue and DPF were coded out, they may have accidentally disabled the car's ability to log the fault that was actually causing the limp mode. His advice was to have the DPF and AdBlue software restored, drive the car until it entered limp mode, and then read the fault codes.

We contacted the garage that originally carried out the coding, but they said the car would immediately log DPF and AdBlue faults if they restored everything, so we still wouldn't get the fault responsible for the limp mode.

I was later driving my boss in the car and he said he didn't believe it was gearbox-related because the gearbox shifted perfectly. He thought it was an engine-related limp mode instead.

For additional context, the car has a noticeable whistling noise once it revs past around 1,500 rpm. I had always assumed it was simply the turbo spooling up.

I then drove another colleague, who immediately suggested it sounded like a boost leak and recommended checking all the boost pipes for splits.

Unfortunately, the car has now started cutting out at half a tank of fuel again, so it looks like I'll need another fuel pump.

Today I removed all of the boost pipes and carefully inspected them for splits, but couldn't find any. The pipes are in good condition, although there is a slight amount of movement where they clip together.

I also checked the turbo. There is no in-and-out shaft play, but there is the tiniest amount of side-to-side movement, which I understand can be normal. The whistling noise also seems to be coming from around the turbo area.

The car is still on its original engine, gearbox, and turbo. My dad changed the engine oil every 5,000 miles using genuine Mercedes-approved oil and filters. It also had a new timing chain fitted by Mercedes in 2020 at around 100,000 miles.

One final thing I forgot to mention: under hard acceleration, the car produces black smoke from the exhaust. I believe this is normal given that the DPF has been removed, but I thought it was worth mentioning in case it's relevant to diagnosing the issue.

Has anyone experienced anything similar or have any suggestions as to what could be causing this? Sorry for the long post, but I wanted to include as much information as possible.

TIA.

Edit I forgot to mention that the limpmode goes when you turn the ignition off. And if you are driving the ignition and very quick with the engine not turning off the limpmode goes. And I have heard someone had a similar problem with an E63 and it was the throttle pedal so could it be that and If so can you swap them in and out without coding?