BAS/ESP light problem in 2000 ML55
 

My BAS/ESP light only comes when I am driving arounf town and when it is quite hot outside +100F (Texas).
After the car cools down a bit, and I restart, the light is gone.
I have already replaced the brake switch.,
Any suggestions would be appreciated.
Thanks
Barry

The only thing that comes to mind is are all your tyre pressures equal?

The tire pressures are not equal, front are 32, rear are 39 based on the
what is stamped on the door of my car.

I didnt phrase my post very well, i meant is one of the tyres very low on pressure to the point that its rolling radius would be significantly different to the other wheels and cause the speed sensors (one on each wheel) to flag a fault?

No issues. I check my tire pressure cold, once every two weeks. The fronts are 32 and the rear are 39 when cold.
The BAS/ESP light comes on initially when the car has been driven for like 2 hours in the summer heat (+100F) and then I shut down the car and when I restart and the light comes on. It goes away, if I let the car sit say for 30 minutes or so for it to cool down.

My guess would be that one of the 4 'abs' wheel sensors has an intermittent fault.
The MB 'star' diagnosis machine should pick up any stored faults.

Check the wiring loom from the two rear abs sensors for any sign of chaffing against the chassis.

Will my scanner pick up the faulty ABS sensor, i think it is called CARSOFT?
let me know
Thanks