First of all, pardon the long post. I am not getting the Nobel prize for literature, for sure!

The car is a 2010j GL 550 w/ on/off road package (option code 430), it just clicked over 150000 km a few days ago. I've had the car since Dec 2019. I have driven it about 1200 km in the past 10 months. Yes, she's mostly sitting around looking pretty and occasionally throwing codes. HA!

Here goes the story. This morning I hopped in the car to get to an appointment and was greeted almost immediately by new gremlins. I didn't make the appointment.

As I was driving down my street, luckily slowly as I was passing by a daycare, I applied brakes gently and the car started making grinding noises, I could feel vibrations through the floor and it came almost to a halt. My brake application was not near enough to engage ABS. The grinding noise somewhat resembled ABS engaging, but at the time I wasn't convinced it was ABS, or only ABS. It felt as if the front wheels were grabbing hard and the car was being pulled back. I have almost no experience with automatic trannies and differentials, so I don't have a clue what a troublesome automatic transmission could feel like, or what differentials might feel like when giving trouble. Here would be a good time to say that the dash flashed a message: something about high temperature in relation to the differential, and to wait a short time. This message I had not seen before. I was startled and too consumed by what had just happened and didn't remember the message in its entirety nor did I have a chance to take a pic of it - it seemed to come up 3 times and then disappeared. I also have a Brake Wear message which is on the dash, it has been there for some time. I pulled over and got the car in park and idling, then waited a minute or so.

By this time, about a minute and a half or so have passed since I started the car and left my driveway, and I am only about 15-20 seconds away from my house. While sitting and waiting, I thought that it would be impossible for the differentials to have an opportunity to heat up beyond normal op temp in such a short time (under 30 sec and speed not exceeding 30 kph), with no obvious strain from the driving surface - the street is laid with asphalt. Ambient temp at the time would have been around 10-15 C.

I decided to give her a second go, so I eased into the street and slowly rolled forward, applying throttle gently and not wanting to get speeds up fast, which would require harder brake applications. I came up to a stop, applying brakes gently, then took a left turn. No problems. Another stop, gentle brakes, right turn, moving along at more normal speeds now - 40-50 kph. At this point I am foolish enough to think that I might actually go to the appointment. So I keep driving - for about 5 minutes. By now I am about to get to a roundabout. Up to this point, I have stopped a few times, with varying degrees of brake application and no sign of any trouble. There is a car ahead of me, I am stopped behind it. It goes ahead and I apply throttle. But the car is having none of that. As soon as I touch the gas pedal, grinding sounds come out and the car kills the minimal speed it has picked up and comes to a stop. My foot isn't on the brake pedal when that happens. I press the brake pedal followed by throttle, gently. The car moves forward, no problem. At this point I am convinced that I am fool for thinking that I would make the appointment. I turn around and head back home. Gentle brake, mostly, and easy throttle. I make it home with little sign of trouble. I am feeling on a couple of occasions a distant grinding (ABS debating about kicking in, but not fully engaging?) when I am easy on the brakes.

As I said, I have had a Brake Wear message on the dash for some time. I am due for rear pads/rotors, which made it in the mail today, of course. Hopefully I will have time to deal with brakes on the weekend.

Once I got home, I pulled the codes. Please see below.

2965
Overtemperature at clutch pack of interaxle differential lock in the transfer case
DTC Status:
Stored

2912
One or more signals sent from control unit N47-5 (ESP control unit) via the CAN bus is implausible.
DTC Status:
Stored

5601
L6/1 (Left front speed sensor) : check installation position of sensor
DTC Status:
Stored

9110
A17/1 Left front Keyless Go door handle) : Permanently actuated
DTC Status:
Stored

923A
M21/8 (Left vent window mottor) : Short circuit to ground or open circuit
DTC Status:
Stored

91DF
Component Ambient illumination of the line to the component has a short circuit to postive or open circuit.
DTC Status:
Stored

905d
The fault code is not found in the database.

994513
Contact strip 2 for anti-pinch protection has a malfunction. There is an open circuit.
DTC Status:
Stored

I think 2965, 2912 and 5601 are all related to my experience above. I suppose first thing would be to change the wheel speed sensor and see if that changes anything? If it does not, is the ESP module next? My big concern is the temp code for the differential. There is hardly anything online about this message. Surely I can't be the first one seeing it.

The rest of the codes seem unrelated to this problem, or do they?

Most recent work I have performed on the car over the last 2-3 weeks: Service B mostly (except brake fluid flush): Oil and filter change, visual inspection of underside (boots, bushings, suspension, ball joints, etc.), fluids (remove/replace brake, windshield washer, coolant caps). I am probably forgetting something from the Service B schedule. I had to remove the front skid plate (metal in my case) to expose the oil pan (I did a gravity drain, oil was warm) and underside for the visual inspection. All looked good.
Replaced rear left hydraulic shock.

Diff fluids are on my radar, but haven't got them done yet, mainly since I don't drive the car that often or far.
Transmission fluid/filter to be done by the MB dealer: TBD.

Many thanks for making it to the bottom of my post!

 

Forgot to add the 905d code description which I found online

905D- Component F58kH (Circuit 15 relay) is defective or missing, or the feed line has Open circuit.

 

Can you distill the post into 25 words or less?

 

Car goes ggghhhhrrrrrrr, dash shoes some gibberish I don't remember exactly, I drive around, car goes ggghhhhhrrrrrr again, I go home. What's wrong?

 

Are both diff locks engaged without you selecting them to be?

weird things happen when these cars aren’t regularly driven. I think the front and mid diffs in the x164 EORP package are electrically controlled... you may have A weak battery that’s causing the switchgear and servos to lose their minds and do uncommanded engagements.

That would acccount for grinding noise and overtemp conditions, and some of your codes.

 

Agree that selectable 4WD systems need to be manipulated from time to time. Locking differentials and two speed transfer cases need exercise, because the default is that they don't get exercise. I had a Toyota 4Runner with locking center diff and two speed transfer case, and the system needed to be run through the motions a couple times per year to remain functional.

 

This is also why you never buy a malljammer G wagen driven by Karen - none of the diff locks will work because they’re all hydraulically actuated and have never been used, and are all gummed up and not properly functioning. Either stuck off or on.

 

Good question. I didn't add this to my original long-winded post, but the diff lock dial on the center console and the dash were not indicating the center or rear diff as being locked when I was driving the car. I couldn't tell you if that changed when the grinding was actually happening, though. The dial's position was on Auto.

The battery was replaced by the selling dealer (not MB dealer, but another major brand - VW) before I bought it so it is a year old. I have a copy of the work order which they completed. According to the work order, they used a replacement MB battery, but I did not verify that by actually looking at the battery itself. Not sure why they did that, rather than opt for another battery, but that doesn't matter, really. Easy to verify and also gives me an opportunity to check voltage at the battery terminals while I am in there. When I reset the service interval, I was running the motor so the voltage on the dash was above 13V, but I don't recall the actual value, didn't pay enough attention to it at the time. The alternator will be pushing above 13+V, sometimes 14+V when the motor is running.

I try to give her a run once a week or so, for at least 30 min - 1 hr and aim for intercity trips, rather than city stop/go traffic and multiple motor start/stops. In any given week, it usually ends up being a mix of city and highway driving. Obviously, by the mileage I've put on her in the last year, I'm not covering a whole lot of distance.

This is great to know. When I got the car last year, I took the first opportunity I had to test the diffs. I did that on a gravel surface and locked/unlocked them a few times. They were engaging/disengaging properly at that time, but I haven't needed to use them since so perhaps it's time to run them through their paces again.

I will report back on the battery state and the diffs.

 

Your vehicle may have an auxiliary battery that should also be replaced as regular maintenance.

 

I tested the battery today. It was low:12.3V. After about 4-5 hrs on the trickle charger it was topped up at 12.5V. I scanned codes again and this time I got two new ones related to the front seat belts.
The code was present for both the left front reversible emergency tensioning reactor (RevETR_LF) and right front reversible emergency tensioning reactor (RevETR_RF).

U012100
Communication with ESP has a malfunction
DTC status: Current

I cycled the differential selector before I started charging the battery while the car was stationary - auto to center diff to rear diff to center diff to auto - sev a eral times. The dash indicator was displaying correctly the engaged/locked diffs. I took the car up and down my driveway, using small steering inputs with the center diff engaged and center and rear diffs engaged in forward and reverse. I did not get any complaints. I'll take advantage of Sunday's early morning lack of traffic and get the car on the road for a bit, but I suspect the differentials are not an issue here. I'll clear codes as well before I get going, scan codes afterward and post results.

 

Today I got the car rolling for a bit. The dash greeted me with the differential and temp too high message very shortly after I got out of my driveway. I noticed that when that message appeared, the diff lock dial on the center console was not lit (normally Auto would be selected/lit). While looking at the buttons/dials, I also noticed that my ADS was in Sport mode and I could not change it by pressing the button. I kept driving gently until I reached a large parking lot about a minute away. I turned off the car and restarted it where I got a few more messages on the dash - air suspension malfunction; EVB, ABS, ESP Inoperative, Diagnosis/Rig Test; ABS, ESP inoperative, See Operator's Manual; Run Flat Indicator Inoperative. ABS and ESP lights were lit constantly inside the speedometer.

I cleared the codes from last time and ran the scanner once again, some new codes were captured this time. Full list of codes below:

D409
No CAN message was received from control unit N47-5 (ESP and BAS control module) (171/203/209) or from control unit N47-5 (ESP control unit) (164/219/251/216/221) or from control unit N47-5 (ESP SPS [PML] and BAS control unit ) (211/215/220/230 from control unit Brake system.
DTC status:
Stored

U140900
An implausible left front wheel speed signal was received.
DTC status:
Stored

1425
Wheel speed signal is implausible.
DTC status:
Stored

5245
Check component Y53y1 (Left rear solenoid valve 1) in assembly Y53 (left rear axle damping valve unit).
DTC status:
Current and stored

5106
L6/1 (left front speed sensor): Check installation position of sensor.
DTC status:
Stored

5101
L6/1 (left front speed sensor): Carry out visual inspection.
DTC status:
Stored

5450
Roller dynamometer mode is activated.
DTC status:
Stored

9110
A17/1 (Left front Keyless Go door handle): Permanently actuated.
DTC status:
Current and stored

923A
M21/8 (Left vent window motor): Short circuit to ground or open circuit.
DTC status:
Stored

91DF
Component ambient illumination or the line to the component has a short circuit to positive or open circuit.
DTC status:
Stored

905D
The fault code is not found in the database.

994513
Contact strip 2 for anti-pinch protection has a malfunction. There is an open circuit.
DTC status:
Stored

I restarted the car. The diff lock dial returned to life with Auto lit up. ADS was still stuck in Sport. I drove the car with the center diff locked (as indicated by dial and dash), but I don't think that it actually did lock, because I did not have any tire skipping when making turns. I wonder if that was because of the Airmatic fault. I am not 100% certain, but I didn't think that Sport mode and diff locking were selectable at the same time.

 

I think your long period of not driving the car may have burned out a wheel speed sensor - these are prone to failing when voltage drops below a certain keep-alive level. The failed wheels speed sensor then defeats esp, speed sensitive steering and brake assist system which in turn may cause your other issues.

i would clear all codes, wait for the wheel speed sensor one to come back and then do both sensors on that axle. It’s fairly cheap and a very easy job.

 

I think the wheel speed sensor error comes up as soon as the car starts moving, if I have cleared the codes beforehand. If I clear the codes and just start the car, I don't think it pops up, but I am not entirely sure about the latter, to be honest.

I have a sensor in the mail, which should be in hand this week. (A downside about where I live is that I have to order parts online and wait a week for them to get here. Even the closest MB dealer will take a week to get parts to my door - they are 2 hrs away). I looked at the sensor and almost took it off earlier this week but decided against it then. I was tempted to take it off and spray brake cleaner into the hole to clean the tone wheel (turn the wheel while blasting it with brake cleaner) but I wasn't sure if that brake cleaner would end up on other parts where it shouldn't. I wasn't in the mood to remove the caliper/rotor to expose the tone wheel. If the sensor is dead, brake cleaner wouldn't do any good.

I guess running the car once every week or sometimes once every two weeks may not be enough and I need to raise my game and go on drives more often.

 

Ok but do both on the axle - otherwise the other one will fail very quickly.

 

I ran the ESP datastream this morning while driving. Should have thought to do that earlier, but didn't. I expected to see one sensor not send any readings, but all 4 were indicating motion and measuring speed. I didnt have time to go through the logs thoroughly yet. Will do that this evening. Since I'm getting readings from the presumably faulty left front ABS sensor, shouldn't it just not send any readings? For example, as if it were disconnected.

 

The surprises keep coming. The car was parked 8 hrs after the morning drive. I got in it to head home and when I started the car, the messages on the dash were nowhere to be found, except my brake wear message, which has been around for a while. I didn't get the brakes done on purpose so as to not to introduce any changes to the car until I can sort out the current problems with EPC and ABS.

The ADS button was not lit (auto setting) and the diff lock dial was lit on Auto. I drove home, while running the EPC data stream to collect some additional data. The only thing I could notice while driving was when braking, the ABS would kick in slightly. I felt it was the lest front wheel (which has the offending ABS sensor). I did another code pull as well when I got home, clearing the codes first, stopped/started the engine and recorded codes in the EPC/ABS and Airmatic modules. I am leaving the Keyless Go and rear interior lamp or hatch electrical codes out of the equation at the moment as I am not concerned with those - I didn't look if those came back or not. I got the following codes related to EPC and ABS:

U140900
An implausible left front wheel speed sensor signal was received
DTC Status:
Stored

1425
Wheel speed signal is implausible
DTC Status:
Stored

5245
Check component Y53y1 (Left rear solenoid valved 1) in assembly Y53 (left rear ascle damping valve unit).
DTC Status:
​​​​​​​Stored

The datastream data consistently displayed values from all 4 corners for the drives this morning and this afternoon. I was seeing similar values from all 4 corners when driving in straight line, and reasonable/logical differences when turning left/right. For a moment I was questioning if the sensor was really at fault here, or if there were some other gremlins at play here. What are the chances that the SAM is to blame rather than the sensor? Is my MBII scanner smart enough to blame the SAM if the SAM were reallyat fault?

I also did some datastreaming for the follwoing components:
A7/7b1 (BAS diaphragm travel sensor)
B34 (ESP brake pressure sensor)
Steering angle sensor
Rotational speed
Latteral acceleration

to have a closer look at what the ESP brake pressure sensor values were. Not sure I can make much sense of the values other than they were increasing/decreasing when I pressed/depressed the brakes, respectively.

Highest value for B34 was 19.4 bar with a corresponding A7/7b1 value 16.38mm. That would have been logged with me braking harder than normal, which I did intentionally to test the ABS. It did come on, although I didn't think it should have as I felt the tires had lots of grip left before they should have broken loose. The braking was done in straight line on ashpalt surface. I've taken that route lots of times and stopped at that light on several occasions, with various brake inputs. I did not think today's brake input was higher than others in the past.

 

What is the next step? Are you ready to start replacing parts?

 

Still waiting for parts to come in the mail. I might see them tomorrow or Thursday.

 

Time for update: I received the ABS sensor in the mail and installed it today. I had only ordered one (I opted for Delphi) not thinking that I should replace both, so I only replaced the offending one on the left wheel. All codes I was concerned about are gone now and I'm back to my one and only Brake Wear message on the dash. The ADS is functional, and so are the diff lock settings. I was happy to feel the tires skipping with the center and rear diffs locked.

I have another front sensor in the mail, also Delphi. I want to see how long the right side will take to bite the dust and I will replace it then. I also have a rear one on hand, I guess I am starting to be proactive.

 

I had a persistent brake wear message even after changing sensors. My rotors and pads were within spec.

I yanked both batteries for a a few hours and it never came back.

 

I've had the brake wear message for some time, maybe 2 monts or so, before the other issues and codes popped up 2-3 weeks ago. The rear rotors are scored and the pads are down quite a bit. I have some more life I could squeeze out of them, but with the weather turning slowly to colder temps here, I'd better to do the job while it's still nice. Or pay someone to do it later.

The front pads are ok,rotors show slight signs of scoring. I'm sure they'll get me through this winter no problem and I'll probably do them next year. Already have the front pads and rotors on hand anyway.

 

Well done. Looks like you've made some progress with the wheel speed sensor.

 

Indeed, amazing how a $50 part chases a bunch of gremlins away.