Soft Brake Pedal, High-Level Brake Light Always On, Fault 01038

[martinch]

Hi guys,

Sorry, another problem thread from me. :(

Relatives got a knock on the door last night to tell them that they'd left their lights on - went out to look, and it was the high-level brake light on the top of the tailgate (and only the high-level brake light - none of the others). The only way to get it to switch off was to open the boot, otherwise it wouldn't go out (I did try hooking my foot under the pedal and pulling up to see if the pedal was partially depressed). However, it's only "partially" on - although all the LEDs are lit up, it only appears to be around 50% brightness, and if you actually press the brake pedal, it brightens, and the other 2 brake lights come on too. From reading on here, it sounds like it's due to a leaking rear washer pipe? Any other causes?

Also, the brake pedal is incredibly soft, and has a lot of travel. When you initially push down, there's so little resistance, it's like stepping in marshmallow. Only after you've pushed it a fair way (far more than on my Fabia - it really does feel like you can push it down to the floor), do you get any resistance, which feels like it's slowly dissipating after a few seconds. Pumping it 3-4 times with the ignition off does result in some more resistance being generated (as it should), but it's not as stiff as the pedal in my Fabia in the same circumstances. The brake fluid isn't low, and the level in the reservoir doesn't "bounce" when pumping the brake pedal, the fluid was (I believe) changed last year, and there's no visible leaks around any of the brakes. Any ideas?

Oh, and to top it off, there's fault code # 01038 ("Central Locking Thermal Protection ; static - no define") that's appeared in the central locking system. If the cause of the high-level brake light being on is a leak, could that cause this code?

I'm sorry that I've only posted trouble threads in here - I don't really know enough about the Octavia to be helpful (although I do at least try in the Fabia forum!). Hopefully it'll be the last one for a while (fingers crossed!).

Any input gratefully received!

P.S. Car in question is a pre-face-lift 2.0TDi estate.

[martinch]

Update: Just tried the rear washer, and it works "fine" (apparently it sprays instantly and at an expected volume), and no liquid was draining out of the drainage holes in the bottom of the boot afterwards. So I guess it might not be the washer line leaking?

[Hauptmann]

The high level brake light fault could be a wiring defect or a problem with the controller.

The central locking fault is very likely a sticking or frozen actuator. Clear it and see if it comes back.

The brake pedal problem sounds like air in the brake line. Bleed out the system ASAP!

[martinch]

Thanks

The brake pedal problem sounds like air in the brake line. Bleed out the system ASAP!

That's what I thought (air in the lines or brake cylinder failure). What's weird is that I believe it was fine a few hours earlier (it was definitely OK on Monday), and has just "gone like it", rather than being a gradual change (not really sure whether it would be a gradual or instant). As it's not been played with, just wondering what would cause air to get in, were that the case.

Edited 25 February, 2011 by martinch

[martinch]

Just an update - the technician/mechanic thought that it was the washer pipe leaking causing the brake light to short, although there was not sign of leaks - the connectors on the pipe were solid (pig to get apart), and there was no staining. Not entirely sure what they did, but the dealer fixed it all under warranty.