Need help from Thailand on CAT light on A8'97

[tu]

Hi! Guys

I'm from Bangkok, Thailand and need your help on my A8'97 ABZ engine. I bought this car fews days ago. My trouble is that CAT light came on once I started the engine. I went to the Audi specialist and use VAG to check this fault. It does not pick up any fault code on this problem. The car was de-cat and replaced with pipe. The engine is still run smoothly, I have no clues on this problem. Any one has ideas?

 

[NIGEL]

HI have you checked the oxygen sensors on the exhaust manifolds or it just might be because you have no cat now. If engine runs ok just ignore it or take out bulb if its that annoying.