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2003 Ml320
Just over 200000 miles
one owner
three lights EPS/ETS/ABS are on
went to mechanic read code and issue noted it be front left (driver side) wheel speed sensor.
In past week I also had Enginee light on as the weather became humid and colder. At same time every cold morning or night when turn engine on the a/c knobs go flashing and light go slight low and high again and the fan starts and off (like their is a breaker) and when I open bonnet to check fuse box I hearing clicking on relay K25 in the front fuse box .
But once I drive for few miles the noise and a/c lights flashing g goes off and heat system begins without intruption.
And today suddenly as coming down a steep hill the brake light on dashboard came on with beeping sound and I noticed a bit of slow spongy brake. So I slowed down and wentto German mechanic shop.
they used scanner many things poped out (see attached please) Quick test report page 1
First, change out the wheel speed sensor. I had the same issue on my project 2004 ML350 and it fixed darn near all of my problems.
Most likely the problem is what triggered your brake issues as well.
If you take your foot off of the brake pedal, do you hear a hissing sound? That can indicate a loose/broken brake booster plunger seal and lead to a spongy/weak brake pedal.
Because yours is a 2003 you are right in the sweet spot for when they changed designs on the sensor. Watch this video and inspect yours to make sure you order the right one (
The only other current code is your secondary air pump. Verify its not a relay issue (mine was). If it needs replacing you can generally fix and rebuild them, they are expensive otherwise. Just search youtube.
Or, as in my 2000 ML320 case, last year, dealer said, it has to start with replacing the main wiring harness, but independent mechanic rightly diagnosed it as bad fusebox. I replaced the entire fusebox and all the gremlins were gone...
First, change out the wheel speed sensor. I had the same issue on my project 2004 ML350 and it fixed darn near all of my problems.
Most likely the problem is what triggered your brake issues as well.
If you take your foot off of the brake pedal, do you hear a hissing sound? That can indicate a loose/broken brake booster plunger seal and lead to a spongy/weak brake pedal.
Because yours is a 2003 you are right in the sweet spot for when they changed designs on the sensor. Watch this video and inspect yours to make sure you order the right one (https://www.youtube.com/watch?v=_-C3FR_2NgY)
The only other current code is your secondary air pump. Verify its not a relay issue (mine was). If it needs replacing you can generally fix and rebuild them, they are expensive otherwise. Just search youtube.
The wheel speed sensor in front left wheel was replaced but now the three lights ETS/ATS/ABS are on plus the Enginee light. The sensor was changed by mechanic in pepboys (paid 50$ sensor+120labor).... I was wondering if the system needs to be reset ?
the brakes now work to stop the car but it feels the ABS system is not kicking in. Also I feel the car hesitates to change gear going from 2nd to 3rd ...
I test drives the car and made hard stops and was okay but no presence of ABS. The tech claims that I need the sensors are responding but the ABS module is not sending info to main the module??? Please advise what to do next ?
Last edited by Newjerseyfrank; 11-28-2020 at 04:41 AM.
The wheel speed sensor in front left wheel was replaced but now the three lights ETS/ATS/ABS are on plus the Enginee light. The sensor was changed by mechanic in pepboys (paid 50$ sensor+120labor).... I was wondering if the system needs to be reset ?
the brakes now work to stop the car but it feels the ABS system is not kicking in. Also I feel the car hesitates to change gear going from 2nd to 3rd ...
I test drives the car and made hard stops and was okay but no presence of ABS. The tech claims that I need the sensors are responding but the ABS module is not sending info to main the module??? Please advise what to do next ?
) can be had a for ~$200, and definitely worth the money if you are going to be DIYing this thing. Pep boys should have cleared it for you if you ask me. Call them up and ask them to clear it.
Not sure about the ABS not kicking in to be honest. After clearing the codes and driving it for a little we will see which codes come back (again, get a scanner) and then we can determine whether that module is at fault. That and im sure its about to get slippery weather so you will find out the old fashioned way.
Re: the hesitating between second and third, sometimes these transmissions do that in the low gears when cold. If it does it when warm, try to use the auto-stick feature to shift between 2nd and 3rd and see if it hangs. If it does, go to the dealer or an MB knowledgeable indy to get the trans fluid/filter changed.
So changed the left/front (driver side) wheel speed sensor but the three lights (ETS/ATS/ABS) stays on even after deleting the codes.
Took it to another tech for advice and diagnosis code check: they have experience with German cars and according to tech who did the latest code checks he recommends 1st changing the wheel bearings for $560 and then do further diagnosis !!! Please see attached the diagnosis results and recommendations. I appreciate if anyone can offer advice and what steps to take ??
Interesting how the indie has recommended a WB change to resolve an ETS/ATS/ABS CEL issue.
Did you follow thru on Dundee's advice prior to all this?
Personally, I'd run as far away from this indy and stay away.
EDIT: after a further quick read thru, are the replaced sensors the correct sensors?
Some of the MLs had a changeover date in the sensors that is dependant on the last 6 digits of your vin#.
You need to verify on the epc if your indie installed the correct part# sensor on ML as they could be vin specific.
They all fit, but they don not necessarily work.
Thank you Khomer2,
what you mean EPC ?
How can I check the right past was installed ?
BTW I spoke to indie tech and he said that he checked the sensor and it works intermediately (the AbS module gets on and off data from the L/F sensor therefore could be wheel bearing.
He confirmed that the ABS pump works and is on.
I asked what else could be the issue other than wheel bearing. He stted that he needs t check why data from sensor is not eaching the ABS module all the time and maybe there is poor wiring connection between sensor to the main block which then reaches the AbS Module AbS therefore he needs two hours of further diagnosis!!!
Please let me know your thoughts ?
Also is there a diagram or video to show how the sensor dat reaches the ABS module and or what other systems/ module blocks it pass through before reaching the AbS module ?
Appreciate anyone with their thoughts on what steps to take next as I am running of patience.
Read thru this post to first confirm the ss part # is the correct part.
It's self explanatory.
EPC= electronic parts catalogue
As for replacing the wheel bearings, confirm with the indie what the WB have to do with the sensor function.
What symptoms are there in his prognosis of failing WBs ?
I see no relationship of WBs and the speed sensors.
If the wheel spins with no apparent failing symptoms then why would you need to replace them?
If he's that confident that it's the WBs, then he should should be doing it on his dime, IF it doesnt solve your SS CEL codes.
I agree with Khomer - makes no sense to replace a wheel bearing. I assume they mean that they want to inspect the hub ring that sends the rotation speed signal to the sensor, but that is easily done through the port the sensor plugs into.
See this photo for reference (note this isnt an ML, just an example of a hub ring) - Also im not convinced they got the right sensor. You can EASILY do this yourself btw with basic hand tools. Here is the part to order.
I would also not take it to this mechanic anymore. Honestly just take it to a dealer at this point, pay the $150 diag fee, and you'll know for sure. I know its a pain in the ***, but I wouldn't pay for wheel bearings that weren't making a noise.
just to let you know that the speed sensor that was installed was not MB OEM part ... it was a generic one made for 2003 ML320.
is that okay or maybe the cause the lights don’t go off ?
see attached invoice
Frank,
Always OEM on these sensors.
We've learned enough to know that generic sensors on MBs can be garbage.
Respectfully, find a qualified indie - He suggested to you, to dole out $$$ for a WB change, yet
he isn't able to perform a simple sensor swap out with an oem part to check it? hummm.
If you read the link, I provided you on David's (2000 E 320 White Wagon) wrong part# issue, you'll understand - it can be that simple (and on your pocket book too)
11-23-2020, 08:11 PM
