Adrian

Guys,
A small suggestion for Carrera 4 owners. It is quite possible that during normal driving of the C4, especially in areas without decent curvy roads upon which you can stick the boot in, that your differential locks system are not getting a regular work out. If you can never recall seeing the little yellow light next to the traction control **** coming on it might be an idea to follow this little tip.
Stop on a straight section of road. Do not shut down. Turn the traction control **** (next to manual spoiler control **** on 1990 and up) to the right for a short time. Must be less than 10 seconds. When the yellow light (LED actually) starts flashing this means that both the centre and diff locks are engaged. Then drive off in a straight line, steering is difficult. At 40kph (25mph) approx the flashing led should go out. You will hear and feel the locks disengage. No warn lights or anything else should occur. Doing this test ensures the solenoid valves are opened, the brake fluid in the lines pressurised and used and that the diff locks themselves have been exercised.
Ciao,
Adrian
911C4

PS: My web site has been updated. " new pages have been added. I do warn you though that the words and the message are quite powerful and emotional.

Roygarth

Hi Adrian

Thanks for the advice.

So in essence the yellow light comes on to tell me the system is working and that I'd better watch out as I'm driving close to limit? May seem like stupid questions but most warning lights come on to indicate something is not working.

Although this light comes on a lot - I drive a lot on windy 'C' roads, I'll try out this procedure this weekend

BR
Piers
1990 C4 Coupe
54K miles

neil williams

The trouble with the light is that once I noticed it going on and off, I could not stop looking at it!

I wish it was in the middle of the dash.

Cheers

Neil

If you ever drive your car on gravel, it flashes like crazy.

krish

Hi Adrian,

Thanks for tip, wll use it.

cheers,
Kris
89 C4

Adrian

Dear Piers,
The yellow led is not a warn light is it a system activated indication. Warn lights can be found in the clock and the main instrument cluster. Call this an old Advisory Light. The warn, caution and advisory colours standard was changed after the 964 was finished on the production line. Mind you Porsche had their own version anyway.
Ciao,
Adrian
911C4

PS: Whilst not an official function of the yellow led or light if it stays on and does not flash this means one of 2 things. Battery voltage is low or a diff lock is still engaged. Good troubleshooting tools.

Wachuko

Thanks Adrian. Will give it a try this afternoon!