C5 hazards under heavy decceleration

[KariM1]

Summary: I want to reactivate the feature

The hazards on under heavy braking was coded off upon import check, as the function was illegal hereby back in 2002. There is a stamp in cars service book indicating this deactivation job done. The car is my'02, RPO 9433.

I've set the feature on in BSI with my Lexia, and it now reads back as it would be on. The problem is, that I have not yet seen it in action. No matter how quick or hard I jump on the brakes, the hazards won't turn on.

I have crawled through all C5 ABS-related documentation in Citroen Service, but have not found clear explanation of which events trigger the hazards. I currently think (not sure!) they should activate if a) emergency braking assistance is active or b) airbags are deployed.

How easily they should activate in practise, experiences anyone?

[Trainman]

Hi Karl,
I had a 2005 C5 and had to "Stamp" on the brakes one day after some clown decided to cross from lane three to exit the motorway. They came on automatically (I was doing about 60mph at the time) and I had to press the 'hazard' light switch to get them off.

[myglaren]

I activated mine one night in similar circumstances to trainman^, but at >110mph.
Scared the hell out of me (and the Land Rover that pulled out in front of me) but they went off of their own accord after driving another half mile (c:a 1km).

You don't need to set the airbags off to activate them, just heavy braking although I have never triggered them with furious engine braking, which should happen.

[xantia76]

Hi,

I have a 51 C5 V6 and I have experiences it a couple of times and it only happens when you stamp on the brakes. Mine have both been on the motorway one at about 80 and one about 40mph.

Hope this helps..

[Homer]

I've activated mine once, in a life or death foot planted hard on the brake situation.

I think you have to brake hard and sudden, as if you are trying to rip the wheels off. Just braking hard isn't enough, you need to really stomp the pedal.

[KariM1]

Sorted out.

From Citroen technical training documents I learned the threshold to trigger the hazards is deceleration of more than 7m/s^2 while speed is greater than 40km/h.

In winter I was driving with studded winter tyres, and those apparently could not exceed the deceleration threshold, not even on dry asfalt. Now with summer tyres the threshold was passed at the very first attempt.

[Citroenmad]

Ive had mine on once or twice. Suppose its a good idea, though it doesnt seem to stay on long after braking, which i thought it would.