I was pretty surprised recently to find that I had almost no brakes at all, coming up to a busy roundabout at the bottom of a steep hill. A quick scan of the panel revealed the two brake warning lights on (mine's non-ETC).

The pump isn't running, but if I jumper pins 2 and 5 on the plug for the pressure switch it runs just fine. As an emergency measure I cracked open the relay and poked it with my finger to run the pump, and here's the weird bit - when it gets to a certain point, the relay pulls in by itself and then cuts off when the accumulator reaches pressure!

Is this a sign that the pressure switch has failed?

Is this a sign that the pressure switch has failed?

Probably, these switches sense both low and high (over) pressure, so presumably it's not doing the former without some 'manual' help....(?)

Scary when you've got no pressure isn't it. A few years ago my ABS pump burnt itself out just outside Lyon. Stopping on the hydrostatic circuit only involved both feet on the brake pedal, especially when you've got a 3 tonne trailer on the back and the brakes couldn't stop it quick enough to cause the over run brake to kick in.

I use this old topic to mention a weird matter ... I had a brake switch error and I bought a new one and replaced it.
I cleared the fault with the Nano and start the car - no errors.
The moment I depress the brake, beep beep and ABS/TC failure.
Same error, 01-07 Brake Switch Failure. Clear fault and will not show up until I depress the pedal again.

Anyone has an idea of where to look, assuming the switch I mounted is not faulty from new?

The cruise control works fine, so I assume the other switch is okay.

Sounds like a broken wire on the brake switch to me or bad contact in the connector. You could pull the brake swtich out and test it with a meter - I would suspect Rave would tell you exactly what it should produce in each state if you were to look at it, but most only have a few contacts so it should be fairly clear when you look at it whats going on (i don't know the p38 well enough to say for sure how many pins it may have, but worst case they usually have 3 or 4, one being a ground if its a 3 pin type and the others swapping between closed depending if the switch is pressed or not)