bholmberg

so, all was going well on my 2003 ML270 with 240k/km.
suddenly, while driving along calmly on a straight bit of road at 100, the BAS/ESP, ETS, ABS, BRAKE, EPC, and Park Brake, lights all came on (along with a warning tone, also the brake lights no longer work, and the speedo no longer works (just stays on 0km/h) and the car just stays in 1st gear... well it wont come out of park unless I use the over-ride, but if I do get it in to drive, it won't go change gears.
(photo of dash - that's a lot of warning lights!: https://*******/photos/1MWMJagS4h3p6iRD6)

- I changed the brake pressure sensor (the one on the brake master cylinder), no change.
- I took out the headlight, and removed the windscreen washer fluid container and checked the wires going in to the abs motor module, all look ok, minimal abrasion.
- I checked all the fuses including F15 and checked the relays, all seems fine.
- I checked for voltage at fuse 15 when pushing the brake pedal - no voltage, so i'm assuming the issue is up the line from there!

to surmise: all 4ets warning lights are on, no speedo, no brake lights, no gear changes.

I have not managed to get it on a merc scanner yet, although booked in to get that done soon. If I can fix or find it before then would save me some cash and significant effort. also any information to keep me informed as to what's going on with my car would also be greatly beneficial. thanks.

I will post updates here, as i'm sure this forum will help others in the future.

Maj. Dundee

Please UPDATE YOUR PROFILE in USER CP to include the year and where you live.

Maj. Dundee

Please post your full vin #.

bholmberg

vin# WDC1631132A403882
does that help? thanks in advance!

Maj. Dundee

Yes it does help, but what would help even more is to update your profile.

Maj. Dundee

The first thing to do is remove both covers to the fuse box and confirm whether or not the Traction Cont. Module is present.

bholmberg

looking at your photo, I would say no.
below is a photo of my fuse box area, both covers removed:

Maj. Dundee

You have to edit your profile. You originally said you had a 2003 which is correct but you listed 2002 in the profile.

Here is a copy of your DATA sheet.

Maj. Dundee

2003 + MLs had the module located at the hydraulic pump. I'm trying to find a work around to test the wires.

bholmberg

ok, so my data sheet says 02/12/2002, but my rego sticker says 2003... so I should stick with 2003 for consistency? - the traction control module does make sense, and i'm very interested in a work around to test the wires, does this unit control the speedo and the brake lights? my suspicion earlier today was a wheel speed sensor, however I can't work out how that would cause the lack of brake lights.

Maj. Dundee

2/12/2002 means Dec. 2, 2002 which makes it a 2003.

As of 2003 M/B eliminated the Brake Lt. Sw. and used the Release Sw. in the Brake Booster to activate the Brake Lights. The Rel. Sw. is internal to the booster and cannot be replaced.

Give me an hour or two to find the right diagram.

Are you able to get to the hydraulic pump today, you probably have to remove the wheel lining to get at it?

bholmberg

yes I think I can get to the hydraulic pump in your diagram today, I will do it now an make a visual inspection. Its currently 20 past midnight where I live, and i'd be keen to see the right diagram in an hour or two, however I might come back to that one tomorrow. shall I post a photo of my hydraulic pump when I get to it? is there something i'm looking for there? or just looking for 'anything obvious' at this stage? and thanks for your assistance, I'm keen to try anything that sounds feasible at this stage.

Maj. Dundee

What you will be looking for is corrosion at the wires leading into the stupid module there.

Did you ever have a problem with the washer fluid reservoir leaking?

bholmberg

never noticed a leaking washer fluid reservoir, however I will do some disassembly now and have a good look.

Maj. Dundee

You would have know if there was a leak if you had to add fluid.

Take good photos of the wire connectors at the hydraulic pump.

bholmberg

connectors look ok to me. A bit of abrasive wear on the sheath where the bunch of wires touches the wheel lining, however doesn't touch the wires yet. the plug itself looks to be in great condition, and appears to be housed in an air tight connection, any way to do a pin out resistance test on these wires/connections?. photos in gallery linked here (hopefully link works):
https://*******/photos/k1T53MifGKGVZqzZ6

Maj. Dundee

Great job with the photos.

Check fuse #27 to see that it is not blown.

If this RED wire is thicker than the red one along side it, then this is wire #1. Both of these RED wires are HOT AT ALL TIMES and powered up by fuse #27.

Count the wires, including the cavities that do not have a wire, until you reach #23 which should be PINK. Further help to locate the correct wire:

#22 is BLUE......#23 PINK.........#24 is GREY

If so, reconnect the connector, turn the key to pos. #2, have someone step on the brake and see if you receive a GROUND signal or a voltage signal at the PINK wire. What was the result?

Then unconnect the connector, turn the key to pos. #2 and introduce a momentary GROUND signal to the PINK wire. Do the brake lights illuminate?

bholmberg

- Fuse #27 looks fine. I also tested the two red wires at the connector, both had 12v as you described.

-when the connector is connected to the traction control module, the pink wire is +ve 12 volts, and that doesn't change when the ignition is on or off, and doesn't change on pushing the brake pedal. (I believe i'm doing this test correctly?, continuity between pink wire and chassis:YES, volt meter -ve on chassis and +ve on pink wire = 12v)

- I found pink #23, I was able to give it momentary ground, and yes the brake lights illuminate.

as an extra piece of information, with the harness unplugged, ignition in off position, that pink wire still has +12v

really appreciate your diagnostics.
a bit of side research has suggested a wheel speed sensor fault. is there a way to test the wheel speed sensors? I had a quick look at them, and they look fine, but I was surprised to find sand inside the hole where the sensors sit. not a lot of sand, but I was expecting a completely clean cavity in there...

Maj. Dundee

The wheel speed sensor has nothing to do with the brake lights not working. What is the code number and what wheel?

You will have to replace your brake booster. Here is the part number.

bholmberg

brake booster... you seem quite sure on this. I see some logic, obviously you see more?
remember: BAS/ESP, ETS, ABS, BRAKE, EPC, and Park Brake lights are all on
I also have no speedo(stays at 0), car won't shift from park(unless I press the over-ride), no brake lights, and car won't shift up from first gear when driven.
does that all relate back to the brake booster?
thanks.

Maj. Dundee

You can't move the shifter because there is no signal to the PINK wire.

You need to have the car completely scanned.

Recheck the wiring harness, strip some of the covering and check for severed wires.

bholmberg

thanks, I will have a really good check of the whole harness. at least I have some background to the issues, and it sounds like a scan is beneficial at this point, while I look at brake booster supply. will update here as I progress.

bholmberg

I had a very good visual inspection of the wires, everything looks fine. I noticed the esp controller had a fair bit of oil on top of it, so undid the 3 screws and pulled it out wondering if the oil had gotten in to the module, however I can't get it open, so just put it back where it came from... does anyone have a wiring diagram for the esp system? i'd be interested to test the wires on this connector just to make sure they are all working as they should. (hopefully will get the MB scan done soon!, just waiting on the local mobile mechanic)

Maj. Dundee

How much does your mobile mech. charge you to come and scan your truck?

Don't you think it is time to buy your own scanner?

bholmberg

probably correct. I was just a little concerned about operation of the scanner. easy enough to use? is the Icarsoft MB2 the way to go?

EDIT: I've ordered the icarsoft MB2. hopefully it's easy to use!