Orry

Hi,


I study for quite some time this forum to get on the right track with my interlock and brake warning light.

My brake light together with the interlock warning light come up when I start the vehicle, as described by Adian Streather the light goes off after 20-30 sec and initial system check. After a while of driving sometimes 5 min or 10 min or 1 min the brake light together with the interlock warning light come up with the central warning light no buzzer and the light in the middle console .I can cancel the central warning light in the dash and middle console, but the brake and interlock warning light stay on.

According to Adrian’s AWD C4 overview it should be related to a low brake fluid level.
I checked the level, there is no leak and the contact in the cap works, the brake pads are OK, the brake pedal travel has also not changed, no tires have changed except that I had to replace one after a flat, but I changed with same brand and size.

Don't know if electronic is acting up or if there is a real problem. As a side note the Airbag light is on for a couple of month, from time to time it goes away but always comes back , once a month the seatbelt light comes on as well and goes away as it came on.

Clock is working like a charm. Any ideas what it could be ?

Thanks Orry

mrmandmman

When you check the fluid is it when the fluid has been compressed?

If not put you key in and turn it to accessory or whatever and you should hear the fluid being compressed. Check the level and fill as appropriate.

mrmandmman

You may need to re solder the clock. I had the airbag and seat belt light on and that solved it. I would do that fix and if the lights come back (or were still on as was my case) take it to a shop or borrow a hammer and pull/reset the lights.

Rocket Rob

How full in your brake fluid reservoir? I've found that you need to keep it at the max, otherwise those error lights will come on.

wellcraft290

also could need to be bled!

Also do you have any battery issues like a low battery or use the car only every few weeks?

jembolt

If it is the fluid level being low, the lights will come back on almost immediately (within a minute or so) of starting the engine. This happened to me last week.

This can also be caused by bad wires/cap/coils etc, if so, the lights come on at random points in a drive. In my case, I solved that problem by replacing the ignition wires.

From the original post, it sounds like it's more likely the second scenario.

wellcraft290

also can be a low battery

Laker

on mine, this was caused by the fluid level being ~8mm below the MAX level , but still well in range (+1
Rob)

Orry

Thanks guys I will look into your hints , however battery is one year old, the level is at max , I will check the compression issue, the car is used on a regular base.

Thanks Thomas

dfinnegan

Note that the level should be checked with the car running and the system pressurized.

Orry

With running engine the level was lower, so I topped it off a liitle bit ,so far no light, I will let you know in the next coiple of days if it stays that way.

Thanks Orry

espenl

Thanx for the tip!

I have the same issue on my C4.. I was suspecting this, but havn´t had time to go to a service center for bleeding. I also noticed the level was lower when engine is started. I guess air in the system does this? Normally compressed fluid shouldn´t make this much difference? Was like 5mm difference on mine.

Atleast now the warning lights are off after starting when I filled a bit more fluid.

Any good tips on how to remove all air in system properly without a hammer? I bled all brakes, but I think maybe the PDAS system has some air in it?

sml

there was a question about 3 weeks ago asking this question.

read the last couple of posts here ...

https://rennlist.com/forums/964-foru...ch-hammer.html

espenl

Thanx for the info!
Ran out in the garage, jacked up the rear and slid under. Found the PDAS valve immediately mounted on the side of the gearbox. Tried bleeding, but nothing came out. There was a rubber cap on the bleeder, but I took the bleed-bolt out (it was totally clogged) and replaced it with a brand new brake-bleed bolt. This time, fluid came out. At first with bubbles in, later clean nice fluid.

I only took a short test drive after, and no lights! I´m doing "rl" testing tomorrow to work.

To summarize the posts, here´s how I did PDAS bleeding without a hammer:
1. Jack up rear of car, ensure to use stands so the car is stable, not only resting on the jack!
2. Turn ignition on
3. Make sure brake fluid is at/above max
4. Get someone to sit in your car, for turning the 4wd lock switch
5. Slide underneeth the rear of the car, and a bit in front of the rear wheels there is a hydralic valve with a brake-pipe entering and a bleed-bolt above
6. Fasten a hose to the tip of the bleed-bolt and the other end into a bottle to collect the fluid.
7. Tell the person in the car to turn the switch clockwise (turn on the 4wd locking).
8. Loosen the 11mm bleed-bolt to bleed the system underneath the car.
9. Close the bleed bolt once the feed stops
10. Tell the person in the car to turn the switch anti-clockwise (disable 4wd locking)
11. Repeat #7 to #10 19 times so that the total is 20 times bleeding.

I also bled the pressure-bulb at the bottom with the spare wheel, and there seemed to be some air in there too.

espenl

A small update. Started car totally cold today, and lights went off instantly, and I never saw them again!
Brakes felt firmer too, but that could just be my immagination.