ABS comes on and car slows down to 30kph

[ohnoburrito]

A couple of months ago the ABS light on my smart fortwo started coming on, but turn off a couple of minutes later, so no action was taken.
After a couple of weeks of this issue, the ABS light would come on and stay on, and the car would refuse to go faster than 30kph, but this could be remedied by turning it off for a minute.

The car was taken to the dealership and we were told that the Lateral acceleration unit/YAW sensor was to blame. The YAW sensor was disabled, by turning it 90 degrees, which we were told would make the YAW sensor send erroneous data to the ECU on starting the car, making the ECU ignore all data sent from this sensor.

For a couple of trips, this seemed to work, however, a couple of days ago, the ABS light returned and the car slowed once again to 30kph.

Does anyone have any ideas as how to fix this? Has anyone experienced this before and if so, how did they fix it?
Thanks!

 

[andy@pcd-ltd]

Hi and welcome.

I think the best way to solve the problem would be to replace the sensor. I have never heard of turning the sensor through 90 degrees to stop the fault.

Do you know what the actual fault codes that were in the system

 

[ohnoburrito]

Hey, thanks for the response.
I got the info for disabling the YAW sensor from the following site;
http://www.evilution.co.uk/index.php?id=233
I figured I could save myself a few hundred by just disabling the sensor instead of replacing it. If the sensor has been disabled, however, and is still playing up, wouldn't that indicate that the sensor itself is not what is at fault?

I myself didn't get told the code - we were just told that it was the YAW sensor that was playing up.
Thanks again.

 

[Boxbrownie]

If you don't mind me saying but disabling the YAW sensor is asking for trouble, it is key to the stability program, which you really do want to keep active!

 

[BachelorDays]

If the sensor is disabled, ABS light would stay On all the time (at least, that's what happens on my W210). Again, on my car I disable it by unplugging it. Car runs fine but ABS/ESP/BAS lights are all On.

I agree with the idea to disconnect it and see if that's what's causing the limp mode. Of course, it does mean the car's stability programs are switched off so it will require the abilities of old about steering and cornering and braking.

 

[ohnoburrito]

the sensor was turned 90 degrees, which I assume disabled it, but the ABS light didn't come on until we ran into the fault of the car slowing down.
Since we have disabled the supposed faulty sensor and are still having the same issues, do you think that the sensor is faulty? Or is there something else to blame?

thanks!

 

[mersum1es]

It's not unheard that yaw sensor fails, but either never heard 90 deg turn would help

 

[BachelorDays]

If the yaw sensor is disabled, ABS light will be On all the time. So the 90 degree trick didn't work. If you want to see if this fault occurs with the yaw sensor disabled, pull the plug on it.

 

[ohnoburrito]

great thanks, I'll go pull the plug and see what happens.

 

[ohnoburrito]

Just following up - I pulled out the sensor and there has been no shutting down to date :grin: It seems the YAW sensor was to blame after all.
Thanks for all the help!