BAS / ABS / EPS Warning lights, Car seems to enter a safe mode (A160)

[Jamesw]

I'll try to keep this concise! After generally 8 to 15 miles of driving my A160 displays the BAS / ABS / EPS warning lights. My best guess is that it is engaging some form of safe mode as it is limiting itself to around 31mph (revs are not limited). I have read several posts on this site so have so far attempted the following:

Full computer test – No errors, no fault logs

Crankshaft sensor replaced – No change (maybe unnecessary as at the time I thought the car was just slowing down, not yet realising it was limiting to 31mph)

Brake light switch replaced – No change

Battery tested – Running well over 12 volts engine off, engine on, lights on, lights off, etc

Also two days ago three of the four electric windows went faulty (will go down, but struggles to go back up, just goes in small spurts). Thinking the two things could be linked by there still being a fault with the battery, I tested again. I linked up to another car’s battery with jump leads, but this did not make the electric windows work, so I am still thinking the battery is fine.

I am loathed to take this back to MB as there is no way of knowing how long it will take them to diagnose the problem at £expensive per hour. I could even end up with a large bill and be no closer to fixing the problem. What next?

 

[Cole@MBS]

Welcome Jamesw, what kind of "computer" did you have it on???

 

[jibcl500]

The battery needs to be checked to make sure all is well, if the battery is ok then get it on some diagnostics.
Whats the history on the car? is it new to you? had any work done recently?

jib

 

[Cole@MBS]

Evening Jib, Strange one above if it hasnst any fault codes, suspect the cars been read with a HHT which hasnt read ESP log!!

 

[jibcl500]

Doesnt sound to me like the cars had a decent diags run, like you say a £50 jobby off ebay.

I think the alternator regulator packs had it, 12v and the battery is still being used not enough juice for the car.
Im also guessing the cars an automatic?


jib

 

[Cole@MBS]

Yes agreed to all, Seen quiet a few front RPM sensors go down on these, could be a poss, again, wouldnt show up on a HHT!!!

 

[Jamesw]

Hi All,

Thanks for your prompt replies. To try to answer your questions:

- "Computer test" was at a Mercedes garage so will be what-ever they do as standard.

- Car is newish to me, but was my parents-in-law from new. 6 years old. Very low mileage (19k). Only recent work was a new alternator. This was actually the first stage of trying to fix this, but I did not mention it initially as I am fairly sure that the independent garage I took it to was dodgy and just replaced it to charge me a fat load of labour time! No other problems in car’s history.

- Yes, is automatic

- Did see a few posts mentioning the RPM sensor, but all said that this would have showed up on the test.

Thanks for your help!

 

[Cole@MBS]

I really cant belive that they didnt have any fault codes!! as soon as the warning lights come on it would have stored a fault!! what dealer did you take it to??

 

[Jamesw]

Took it to Bristol, Cribbs Causeway as that is where I was when it first happened. Comment from them was "as if it had never happened".

 

[Cole@MBS]

I think they prob just cleared the codes to send you back on your way!

No 6 year old A,class is not going to have any codes in it!

Think your best bet would be to find a inde with a star machine and have it read again!

Theres got to be some thing in the log as the light has been coming on!

 

[jibcl500]

Speed sensors MB UK have sold 77 on on side and 70 on the other. Retail at £72+ vat each.

jib

 

[MB TECH WARRINGTON]

Ive Had This Fault Many Times, Wheel Speed Sensors Dont Tend To Put Car In Emergency Mode.

The Cause Of Fault On The 3 Cars We Have Done With All Your Symptoms Was A Faulty Electric Pack In Gearbox, Unfortunately It Only Comes With Valve Body Unlike Other Cars So Quite Expensive.

It May Also Explain Why They Said No Faults Found As The Guy Prob Not That Experienced And The Fault Codes Thrown Up Often Are Blank In Abs/esp Etc With This Fault, It Shows Fault In Gearbox.

Which He May Not Have Linked.

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