88 5000 CS Brake Light Warning [Archive] - Audi Forums

: 88 5000 CS Brake Light Warning

07-22-2008, 02:55 PM
I have an 88 5000CS with 67K. Got it last October and immediately had the bomb and steering pump replaced, along with a bunch of other minor things. Recently, whenever I start her up after not driving for a while, the brake warning light appears after about 5 seconds of idle time. Then after about 5 more seconds it goes away and everything is normal. At that point the brake pedal pressure is where it should be, but on start, the pedal pressure definitely is not where it should be -- thus the warning light. I check the power steering fluid and brake fluid levels also, and both are max.

Does anyone have any ideas as to what's causing this light to appear when starting? Is it a sign of imminent danger?

Thanks in advance. I love this forum.


Harvey Smith
07-25-2008, 02:55 PM
Tony: The Alarm likely coming from switch sensor mounted behind Brake Fluid Reservoir. This has two wires plugged into it. On my 5000S this is a 5 ohm short when key on but not running and then goes open when car starts.. If you carefully unplug one connector with key off the alarm should be disabled both before and when car is restarted.. Then you should never get this alarm. It appears your pressure is leaking off or perhaps some air in system and takes awhile to get up to normal pressure.. There is something acting up tho.. but may be minor if brakes and steering don't misbehave under hard use. There may be a leak somewhere in connections and I would look for that first. The belt on Pump may even be loose.

This sensor apparently could relate to Power Steering, Power Brake or perhaps even Brake System. I believe The Bomb is a Pressure Accumulator used to maintain hydraulic pressure when system is being used repeatedly.

One must make sure to use the right kind of Hydraulic Oil.. Though extremely expensive this is some kind of very special oil, as many Audi Drivers have found out, the hard way!

Hope this helps and good luck.