MBWorld.org Forums - GL Class (X166)

Air Supension Nightmare

Jguz — Sun, 24 May 2026 04:24:03 GMT

I�ve always had the c15561C code because of what i think was a bad valve block but i never thought to change it because the car was fine and drove smoothly and it stayed that way for a year or so.One day i notice that my gl450 was sitting real low on the front end of the car so i go and check it out and i see that the battery had died so i replace the battery and hear a leak coming from my driver side front air bag. after replacing that air bag i ran a level calibration and it was fine all systems were good. i drove it maybe some 15 mi and everything was fine until i went to go drive it back. Once i started driving the car was to the floor and riding was awful bumps all the way home. So i get home and i try running diagnostics and now IM thinking that my OG code has officially caught up to me and now my issue is after replacing the valve block i�m getting a c156c00 code and the vehicle does not raise at all but ride better than before but not perfect looking for any inputs

Secondary Timing Chain - P0011(77)

marecki_IL — Fri, 22 May 2026 19:30:47 GMT

Hi have a question for some of the more technically advanced people on this forum and I hope I don't catch too much heat.

I recently performed the secondary timing chain tensioner replacement on both Bank 1 and 2 on my 2014 GL450 with 140,XXX miles. The job went very smoothly, I marked the chains and sprockets on both sides to be EXTRA sure that the chain hadn't moved while reapplying tension to the timing chains. Pins pulled, new tensioners installed, no movement at all on the timing chains. Reassembly went well (the drivers side is awful if you don't remove the oil filter housing) and everything gets put back together. No leaks, car fires right up, runs smoothly, drives great.

The next day my wife is driving the car and the CEL comes up. P0011(77) - position of the intake camshaft on Bank 1 deviates from the specified value. :wall:

Things I have checked so far.

Timing looks ok
Cleaned and swapped VVT solenoids from intake to exhaust - still have the code after erasing it
Cleaned Cam shaft position sensors
Verified that the reluctor ring is centered in the CSPS port

Is it possible that the reluctor ring moved on its own in the meantime? The car was running perfectly with 0 codes until after I performed this. I have been doing some reading and have come up empty handed apart from the possibility of having to replace the Bank 1 intake camshaft phaser which sounds terrible. If anyone has some pictures of what position the reluctor ring should be in the port hole of the CSPS I would really appreciate it. I doubt the phaser is going bad since everything was running perfectly before and at this point I have almost convinced myself that the reluctor ring has moved.

Can anyone provide some insight into WTF just happened. For some reason there is a good amount of reference on the M276, but nothing for the M278. I have referenced YouTube, forums, Superetka and Alldata and there is almost no info. I have the Foxwell NT710 to help pull data. For reference, Bank 1 intake cam position is showing at 42-43 degrees according to the scanner data:confused:

HELP! I can provide pics upon request and will upload some later this evening when I get home.

Bye to "White Widow". 2015 GL 550

lexnoir — Fri, 22 May 2026 01:21:16 GMT

We had a blast watching people think I was a soccer mom on her way to drop the kids off at practice. Try to cut in front of me in traffic or speeding up when I put my turn signal on to get over. Little did they know I was a brotha with a Renntech tuned GL 550 that would beat the brakes off them and handle the upcoming corner often better than them.

At 122K miles young it was time to say goodbye. I have a 2022 SL 55 AMG and an AMG GT 53. The twin turbo V8s were killing my pockets at the pump. A heavy foot combined with a wife who can't drive for **** meant I was always driving.

I decided to dip my toe (very reluctantly) into the EV market. There are VERY Few EVs I find attractive and Mercedes has a total of zero attractive EVs.

I also don't really need three cars +1 being my wife's car. So I needed something used and cheap. I was leaning towards an Audi e-tron GT, super sexy but the interior is no better than my wife's VW Jetta. I also figured I need to replace an SUV with another SUV. So, I went with an Audi Q8 e-tron. Not impressed with the looks, but I will put my touches on it to make me feel better driving it. Better wheels and definitely a replacement grille.

Thus far, the ride is extremely smooth and the double pane windows and lack of ICE makes it whisper quiet inside. Having owned a few Audis in the past I'm not sold on reliability but we shall see.

Better interior than the GT and the price was right. So, I guess I will see you all around the forums GT or SL. It's been a nice ride (literally).

Before you say it, I already know the GL550 at 11 years old still looks better.

AC Control Valve Identification, smiley face on connector

Sneaky_D — Sun, 17 May 2026 21:32:59 GMT

Can anyone identify if this is a diode or non diode type with the smiley face on the connector.

I had seen it mentioned in some previous posts, but nobody identified it.

2015 GL450 with 7SEU17C compressor

SRS/Left front door crash sensor

Borkox166 — Sat, 16 May 2026 13:27:44 GMT

Hello, I have 2016 GL550 and I got codes B009111 and B009195. I replaced the left front door crash sensor but that didn't not resolve the problem. After replacing the sensor I tried clearing the faults with iCarsoft mb v2.0 but the codes are still present. I wonder if anyone on here has gone through an issue like this with any of the crash sensors and how they fixed the problem. Also if there is a short to ground on the left front door SRS circuit how do you diagnose and locate the short? Is there a way to reset the SRS module? Maybe a simple reset is all its need it but I'm not sure how to do that.
My biggest problem with this is because of that when I try driving the car it will constantly put its self to "P" no matter if I put it in "D" or "R" it will alsmot immediately go back to "P". If I'm fast enough and accelerate before it goes back to "P" it will go but as soon as come up to a stop it will automatically go back to "P".

Any help or advice will be much appreciated. Thank you!

2015 Mercedes-Benz GL450 Overland Build | X166 GL450 Build Thread

hamzainvests — Mon, 04 May 2026 17:24:43 GMT

Hey guys,

Excited to finally be here on Mercedes-Benz World Forums. This is my first post, and I�ve been looking forward to starting this build thread.

A little background on why I�m building this 2015 Mercedes-Benz GL450 into an overland rig.

I moved from Dubai to Houston about 10 years ago, and one thing I�ve always missed is heading out into the desert for long drives. The terrain back home�mainly sand dunes�is obviously very different from what we have here in the U.S., but what I�ve realized over time is that I enjoy overlanding more than extreme off-roading. I�m not trying to build a rock crawler�I want something capable, comfortable, and able to go long distances without sacrificing ride quality.

Back in Dubai, my go-to platform was always the Nissan Patrol. For me, the GL450 feels like the closest equivalent here�just with a more refined and comfortable driving experience.

Here�s why I chose the GL450 for this build:

First, air suspension. Ride quality matters a lot to me, especially in a country as large as the U.S. where road conditions vary significantly. The factory air suspension gives me the flexibility to adjust height while maintaining comfort on long drives.

Second, aerodynamics. I didn�t want something like a Jeep Wrangler or Ford Bronco. As capable as those are, I wanted a quieter, more stable ride�less wind noise, fewer rock chips, and better overall highway comfort.

Third, build quality. This is where Mercedes really stands out. Everything feels solid, tight, and well put together. Even with a roof rack installed, cabin noise is minimal.

Fourth, space. I�ve got two kids, and we needed something that comfortably fits the whole family. The GL platform checks that box without compromise.

And finally, practicality. Even though it�s a German vehicle, this GL was built in the U.S., which makes parts easier to source and maintenance more manageable. I also like to do some of my own work, so that played a role in the decision.

The goal with this build is simple: take a platform that isn�t typically seen in the overlanding world and push it into places where you�d normally see Jeeps, Broncos, and Land Cruisers.

This is step one, and I�ll be updating this thread as the build progresses.

Current progress:

Roof rack installed
Wheels & tires coming next
Running factory air suspension lift for now

Planned:

Wheels & all-terrain tires
Suspension optimization (possibly beyond factory settings)
ECU tune
Exhaust system (still exploring options)

I�ll be posting photos and updates as things come together.

Looking forward to learning from you guys and sharing the process.

Time for new Axles

City Cruzer — Mon, 04 May 2026 00:43:44 GMT

So I've got this vibration in the front end that I'm quite sure is from unbalanced tires. However, I also have the "clunk" coming from the front end under loads and when turning. Who has replaced their axles and what do you recommend other than OEM. My girl is a 2013 GL350.

Thanks!

Gl350 2014 nav/radio screen

milValMaks — Tue, 28 Apr 2026 19:47:25 GMT

Seat warmers work and hazard lights and on button flashes on and off but radio nav back up camera not working. Checked fuse on radio looks good and side 21 amp looks good.

any suggestions?