Help Needed Warning ⚠️ Message Run Flat indicator Inoperative- S350 - 2012

[Sammerc350]

Hello Mercedes Members,

I’ve just Had a warning message appear on my dash, Run Flat Indicator Inoperative, I can restart the Run Flat Indicator on start up but a short drive down the road and the message comes back on. Also my EPS system turns off.

I’ve enclosed some images to show the messages I’m getting.

Just for information I checked my tyre pressures they are all as they should be.

I would appreciate anyone who has had experience with this, and importantly how do I resolve this?

Many Thanks

 

[markjay]

A faulty ABS wheel sensor is the most likely cause.

Get the fault codes read by STAR (or iCarsoft). It will show which wheel sensor has failed.

Probably ~£150 to fix at a specialist.

Less likely but also possible is an electrical fault, e.g. weak battery, faulty alternator, etc.

 

[Sammerc350]

Thank you Mark Jay,

Out of interest I voltage checked my main battery with a multi meter and the main battery was lower than it should be, I know it’s not the auxillary battery because that’s brand new. So hopefully it is the battery causing the issue, although would that stop the EPS system working and throw up my ABS light?

 

[markjay]

The wheel sensors send electronic signals to the ECU, so if the voltage drops then the system becomes unreliable and the ECU will preemptively shut down these systems for safety reasons, I.e. because incorrect input from the wheel sensors can cause a crash.

What was the battery voltage?

 

[Sammerc350]

Checking the voltage with ignition off showed 12.08 - leaving the multi meter attached I started the engine the reading dropped down to 8.98 then when the alternator kicked in the readings were up around 14.4 ish.

We went for a long drive to see if a run would put a good charge into the battery after a couple of hours out came back switched the engine off and checked the voltage and it was 12.02 less than when we started, which was a surprise

 

[markjay]

Do you have a trickle charger (e.g. CTEK)? Charging while driving can take a very long time.

 

[Sammerc350]

Yes I did buy one recently that would charge an AGM battery, the only thing I found out was that if you remove the battery without maintaining a charging connection you can have all sorts of issues, which is typical of Mercedes, it could just be simple like most cars

 

[Sammerc350]

Mark Jay, two other points worth mentioning, I posted in the forum that when I switch the ignition on and go to start the car the digital speedo displays lines across the dash and then the speedo cluster switches off, in comes back on after 10 seconds.

Also the electric auto seat entry movement is now not working.

 

[Riva811]

Mark Jay, two other points worth mentioning, I posted in the forum that when I switch the ignition on and go to start the car the digital speedo displays lines across the dash and then the speedo cluster switches off, in comes back on after 10 seconds.

Also the electric auto seat entry movement is now not working.

I would replace the battery anyway. Did you test the battery after it was sitting for at least 8 hours? Either way dropping to ~9 after you start the car is bad enough. I know first hand the electronics in these cars are no joke and cause a lot of ghost issues when the battery plays up.

 

[markjay]

I would start by resolving the battery issue (either charge/fix it if you can, or get a new battery if need be), simply because this is an issue that you will need to address anyway. Then see what happens with the other faults, once the battery issue is resolved.

In any event I still recommend that you buy an iCarsoft or a Carly.

With regards removing the battery from the car, you can buy a 9V 'memory keeper' device off eBay or Amazon, which should be OK for keeping the various bits in memory while the battery is removed.

That said, AGM batteries are best charged via the car's dedicated charging poles in the engine bay, and not directly via the poles on the battery. This is because the battery management module keeps data on charge input and output, and charging the battery directly can confuse the ECU and potentially cause all sort of faults until the ECU memory is reset via STAR.

 

[Sammerc350]

I would replace the battery anyway. Did you test the battery after it was sitting for at least 8 hours? Either way dropping to ~9 after you start the car is bad enough. I know first hand the electronics in these cars are no joke and cause a lot of ghost issues when the battery plays up.

Thank you Riva,

I appreciate your input, Yes I did test it after 8 hours and it showed the readings I mentioned above. Yes you are right I really don’t want any ghost electrical issues with this car, unfortunately because of lockdown etc the car has probably travelled 50 miles in 12 months, not good.

 

[Sammerc350]

I would start by resolving the battery issue (either charge/fix it if you can, or get a new battery if need be), simply because this is an issue that you will need to address anyway. Then see what happens with the other faults, once the battery issue is resolved.

In any event I still recommend that you buy an iCarsoft or a Carly.

With regards removing the battery from the car, you can buy a 9V 'memory keeper' device off eBay or Amazon, which should be OK for keeping the various bits in memory while the battery is removed.

That said, AGM batteries are best charged via the car's dedicated charging poles in the engine bay, and not directly via the poles on the battery. This is because the battery management module keeps data on charge input and output, and charging the battery directly can confuse the ECU and potentially cause all sort of faults until the ECU memory is reset via STAR.

I appreciate your input Mark Jay,

I’ve not heard of a 9v memory keeper, are these worth while? Also thanks for the information on the charging poles that was super helpful, I never knew that. Could I also use another cars battery by using jump leads to keep the charging system live? Would the car providing the charge need to be running or just connected?

Also could you point out where I will find the charging poles in the engine bay.

Many Thanks

 

[markjay]

I don't know where the charging poles will be on your car, you'll need to check the owners manual, but this is where they are on mine (C-Class), if this helps:

 

[Sammerc350]

Thanks Mark Jay,

I will have to dig my owners manual out, would you say it’s better to use a second car to main an active charge or use one of those memory keepers?

 

[Sammerc350]

Brand New Mercedes Battery Replaced, unfortunately the Run Flat Indicator, EPS, ABS warning lights remain on. I can clear them while the car is stationary but when the car starts to roll the warning lights come back on

Any ideas?

Also I’m having a NOX sensor issue, it doesn’t just rain it pours..

 

[DSM10000]

As said in the early posts, you need to get the car to a MB specialist to get the fault codes read.

The NoX issue is a common one and it seems that in many cases Mercedes are replacing the sensors FOC

 

[Athey]

I’ve got to do the rear abs sensors, so will do a full write up on how to do it with pics. Hopefully this week weather permitting.

 

[alexanderfoti]

when the car starts to roll the warning lights come back on

As it happens when you start to move, its very likely to be a wheel speed sensor, or reluctor ring issue.

 

[Sammerc350]

Hello Mercedes Members,

I’ve just Had a warning message appear on my dash, Run Flat Indicator Inoperative, I can restart the Run Flat Indicator on start up but a short drive down the road and the message comes back on. Also my EPS system turns off.

I’ve enclosed some images to show the messages I’m getting.

Just for information I checked my tyre pressures they are all as they should be.

I would appreciate anyone who has had experience with this, and importantly how do I resolve this?

Many Thanks

Update:

I changed my Wheel Speed Sensor and the EPS, ABS, Run Flat Indicator Inoperative warning lights went out Had the car scanned not at Mercedes, found it was the sensor, replaced the sensor myself, issue resolved, and it’s super easy to do..

Not every issue your car has needs taking to a Mercedes dealer, no matter what your told, do your research, check You Tube for Professional How To Videos if you need Visual Help, have your car scanned by someone who has a Mercedes Xentry Diagnostic, then acquire the part and fit it yourself.

If you like doing any kind of repairs you can save yourself considerable money, If you don’t care for repair of any kind, then there’s always a Mercedes Specialist happy to assist, but just remember you will be % better off in every way by using a Independent Mercedes Specialist rather than the usual poor service provided by Mercedes Main Dealer