Dreaded “ABS and ESP Unavailable” + “ Run Flat and Tire Pressure Monitor Unavailable” 2 Messages Returns ☹️

[Submariner1]

Q. As I heard low brake fluid could cause this. I checked my brake fluid - at first I thought the reservoir was totally empty - no it was completely full, right up to where the filler neck is, miles over maximum. Could this on a searing hot day, inclu. a 1 hour traffic jam, crawling forward one meter at a time, and the rest a long fast drive, circa 3.5 hours in total cause this problem? Would brake fluid expand when brakes are red hot?

Note all 4 Sensors were changed 8,960 miles ago, in May 2018 @ 44,000 miles . Could they go again … so fast?

Main dealer had changed the brake fluid every 2 years, so done in Jan 2022 with no problems till now .

Same ABS RF Messages Problem in May 2018, details:
Had this in May 2018. Long saga appearing, disappearing then reappearing. This was solved at a shock cost of £823 by main dealer.
I say shock, as when I put the car in I was told one sensor was circa £98 and the other £92.
Loads of tests, incl Electronic Park Brake etc. apparently determined one Front and one rear ABS sensor was intermittently icky!
its recommended to change both on the same axle, so 4 Sensors for me! And it worked.
Current Problem:
Yesterday drove 120 miles to coast, 8.20 am till 12.00 noon, average temp 32C, near the end hit a 1 hour smash up queue, (horrific) moving 1ft at a time, brake move, brake move. At the end of the Journey, turned car off ( I think I saw a yellow flash on dashboard). Restarted car, and both messages. WTF. 4 years and only 8,980 miles and one or more ABS Sensors has gone.
At the end of the day circa 8.pm, car sort of cooled down, sat in sun circa 29C, I restarted both messages there . Reset the RunFlat Tire Pressure Monitor. ( note I have neither of these options , just good old valves, but got the message last time so why not) . Started, Drove off dam its still there. Then 300meters later ABs Light and Yellow warning triangle went off. Stopped car and restarted No messages.
Yippee a glitch, No … 97 miles later back they came. Restarted Run Flat crap again and a mile later still there and still there this morning.

This evening when it had cooled down (from 40C to 29C) I reset Run Flat and bingo 400 meter down the road lights go out and stay out!
But sure it will come back….
Note checked tyre pressure both fronts 34 psi - both rears 37 psi - so perfect! Then I checked the brake fluid as per top Q?
No I have not checked the voltage, but last time checked alternator was chucking out 14.6V .
I will check the voltage tomorrow.

 

[malcolm E53 AMG]

I’d check/replace the brake light switch on the foot pedal cheap as chips and prone to bring on the ABS/ESP warnings when failing - you certainly tested it out yesterday

 

[ajlsl600]

Interesting on brake light switch
I had almost same, except mine would not release the parking brake on my drive! Used icarsoft mb to clear faults and away we went, particularly stupid design, for owner, great for benz. I had right hand rear wheel sensor fault. Tho it did not clarify if rh from sat in D seat or from looking at front of car? Anyway a mate changed it and aux batt. No faults shown, which is not of much help as once cleared the lights would often stay off all day, or not! Then all come on next am. I v suspicious that it's software trained to send me to top up the dealer money pot. We see. I am on mine in Burkina Faso so won't know until Sept. But I can tell you the whole, very similar to your experience ruined my last few days in France. And I won't be buying another euro 3+ car. Makers just have not got on top of all the shxxe they have bolted on to them, OR have they?

Note I also saw tyre warning and also don't have that on my ml!

 

[Wighty]

I think any car fault to do with tyres on the hottest day of the year I would ignore and wait until a drive on a cooler day is possible after rechecking tyre pressures at the start of a drive .
If you have never changed the brake light switch as @malcolm210 says , they are £15 and 5 mins to fit .

 

[alexanderfoti]

Won't be brake fluid

Most likely another wheel speed sensor, read the codes to determine which

Less likely, a bad battery giving poor voltages, these also trigger ESP comms faults a lot on 221/216's

 

[ajlsl600]

Won't be brake fluid

Most likely another wheel speed sensor, read the codes to determine which

Less likely, a bad battery giving poor voltages, these also trigger ESP comms faults a lot on 221/216's

If it's another(mb) speed sensor that would, if fitted correctly confirm my opinion of mb sensor quality.

 

[alexanderfoti]

If it's another(mb) speed sensor that would, if fitted correctly confirm my opinion of mb sensor quality.

At least they are consistent.

 

[Submariner1]

Won't be brake fluid

Most likely another wheel speed sensor, read the codes to determine which

Less likely, a bad battery giving poor voltages, these also trigger ESP comms faults a lot on 221/216's

Thanks I checked battery this morning 12.4V engine off ( normal for this newer battery ) and engine running 14.2V which is pretty much its normal.
odd the first sensors lasted 44K mikes and now these can not make 9,000 miles.
As they are reasonably new can I just change one ( I know MB recommend changing both on the same axle.)

 

[alexanderfoti]

Its likely only one that is broken. Probably a manufacturing defect. Do sanity check the lot though, there could be a broken cable etc. Best not to jump to conclusions.

 

[ajlsl600]

At least they are consistent.

Suspect it like new car batts(and that will change) origional last 10 Yr then it's every 2 or 3. Suspect same on sensors cept statistically shud make it 360 + 1

 

[ajlsl600]

Think one I bought last month was near 138 for somat prob cost 5 quid to make.

 

[Submariner1]

Just a thought I do Karcher my car and the wheels and half heartedly underneath periodically. Could this be damaging the sensor or wire?
Note its the Industrial Low Pressure High Volume type. Says 9.8L/ min 13.8 MPa Max 19 Mpa
WTF is MPa ? Megapascal? Per google looks like 2,000 psi Max 2,755 psi
E.g. Removing stains in brick my neighbours £200 domestic Karcher has higher psi and removed them easily, this one takes for ever so defo does not have massive psi. Mind you 2000psi sounds a lot.

 

[alexanderfoti]

Just a thought I do Karcher my car and the wheels and half heartedly underneath periodically. Could this be damaging the sensor or wire?
Note its the Industrial Low Pressure High Volume type. Says 9.8L/ min 13.8 MPa Max 19 Mpa
WTF is MPa ? Megapascal? Per google looks like 2,000 psi Max 2,755 psi
E.g. Removing stains in brick my neighbours £200 domestic Karcher has higher psi and removed them easily, this one takes for ever so defo does not have massive psi. Mind you 2000psi sounds a lot.

No, the sensor connector in the arch is behind the arch liner, and the wheel side is completed sealed epoxy

 

[Submariner1]

Suspect it like new car batts(and that will change) origional last 10 Yr then it's every 2 or 3. Suspect same on sensors cept statistically shud make it 360 + 1

Don’t get me on new MB Batteries.
old style never had a problem. Worked in Holland for 15 years. Car left standing at Heathrow Mon to Fri, never even thought about it. 3 weeks in Barbados always started.
As this car was 7 years old, belt and braces I replaced Battery that was always circa 12.6V standing unused. So stupid!
Now lucky if its 12.4V often 12.2V after shutdown with leakage of 0.04 amps.
First one only lasted 8 days - replaced as defective at 11.6V, car all checked out. The replacement constantly needs CTEK trickle charging ..l utter shite!
and the morons downgraded the original from 95AH to 92AH.
really gives me confidence in Electric Cars !!
just waiting to see how long their batteries last.

 

[Submariner1]

No, the sensor connector in the arch is behind the arch liner, and the wheel side is completed sealed epoxy

Thanks Alex.

 

[Submariner1]

I think any car fault to do with tyres on the hottest day of the year I would ignore and wait until a drive on a cooler day is possible after rechecking tyre pressures at the start of a drive .
If you have never changed the brake light switch as @malcolm210 says , they are £15 and 5 mins to fit .

Almost worth doing just to rule it out
Changing all four sensors cost me £823 last time. I thought they were going to change one sensor at £98 ! So seemed sensible not to go to MBS … big mistake!
Having reset the Tyre Pressure - Run Flat indicator …. No messages.
think I will just drive it till they come back , you just know they will and call Mobilo to find out which one it is

 

[Submariner1]

Last Question.
If its just one faulty sensor; bearing in mind all 4 are only 8,900 miles old.
If they are still the same part no, and not a a superseded part, i.e. the replacement is still the same part number and not a possibly revised part with a slightly different spec. can you just change the faulty one?

Normally I would always go with MB recommendations but if they are such crap quality whats the point as another one will probably go next week!

 

[Submariner1]

Got my MBII Code reader out. I really have no idea how this works, or where to look. Basically looked for any fault codes on the Car, as there is no manual as such - only tells you how to connect it.
Looks to me like an historic “Left Front Speed Sensor” (NB: having cleared the RunFlat Tyre Pressure N/A msg. There are now no messages on Dashboard and all looks and runs OK for the moment - but based on my past experience these always come back)
Q1. But, Which is the Front Left Speed Sensor? Is that the Front Passenger (Nearside) ?
At least it look like just another crap sensor, and not the ESP or ABS Module??? Which I assume are a fortune £.
under ABR section




Note I do not have Distronic so ignored this next one

Another Front Left Sensor Fault code.

Next one confirms its from the front axle. Ergo the Left Front Sensor is faulty or more correctly was faulty for a while?


Because last time they said this could mess with the fancy EPB I looked under this:-

Guess if the sensor was flaky this Control module would report this to the EPB control module. Seems logical? But WTF do I know.

So I assume my front left Sensor played up, and now its working shows this as ‘Historic’ .

 

[Wighty]

Make a note of them as they are historic , then delete and see if the re occur .

 

[KennyN]

Q1. But, Which is the Front Left Speed Sensor? Is that the Front Passenger (Nearside) ?

Yes , had a similar sensor code on my car (Rear / Right) which was the offside.

K