Originally Posted by ALi-B;1:thumb:0235442

Put it this way, Cats don't just 'fail' there is always a cause, and this must be found first.

Unless you whack them with a big speed hump. (Doubtful on a Tribeca unless its been offroaded).

OR most likely the car has been operated for a significant amount of time with an engine fault. This can be lumpy runny/lack of engine smoothness, lack of power, poor fuel consumption, check engine light, or just a strong smell from the exhaust (due to the cat being overloaded). A runing fault, even a minor one can over time overheat and melt a cat and render it ineffective.

These running faults MUST be diagnoised and fixed before attempting to replace the cats. Otherwise teh new ones WILL meet the same fate.

These cars use two sensor to ensure the is cat is present and operating correctly. They are also sometimes used to calibrate each sensor as well a provide adaption to the engine's fuel mixture. Now, some cars, like VWs are clever, their systems are actually quite good at working out if the sensor is at fault or teh cat is and the fueling readapts automatically once rectified

But on the other hand some systems are stupid; like the Denso system in a Volvo v70....it throws up cat errors when a sensor is dodgy and refuses to readapt teh fueling once the rogue sensor has been found and replaced. This leads to teh car running bad mixtures, still throwing up ramdom codes and eventually destroys the cat from it overheating.

By the way, I'm not assuming a sensor fault, its just one of the many things that needs to be checked....other common issues include vacuum leaks, valve timing issues and a faulty injector(s) amongst other things.

Originally Posted by ByByR1

I don't know the code it threw up as the wife took it in whilst I was at work, it don't say anything on my bill either. £81 to check it with the reader. day light robbery if you ask me.

Originally Posted by rob84

Thats because we look after our customers