The key point to remember is that CATs are not simply part of the vehicle’s exhaust system, they are an integral part of the car’s sophisticated emissions control system and must be
treated with care. Arvin Replacement Products Ltd. recommend that you should not fit a CAT without having the appropriate equipment to test the ECU or Lambda sensor.

• Identify if a CAT is fitted. (If necessary check VIN/engine number). The CAT will be the first box in the system.

• Always determine the cause of emissions test failure BEFORE replacing the CAT, ECU, Lambda sensor etc.

• Do not remove and inadvertently discard the old CAT or replace it with a non-CAT exhaust. The car will not run properly if you fit a non-CAT exhaust.

• Do not replace a CAT as part of a fault finding exercise.

• Do not remove the CAT if you are simply replacing the centre and rear silencer box assemblies.

• Always ensure availability of replacement before removing a CAT. A customer cannot use the car if the CAT is removed.

• Always conduct MoT emissions test after replacement except where replacement follows accident damage.

• A typical system with always use new CAT compatible gaskets during CAT replacement. Use Silicon-based rubber mountings in the CAT area. Do not use exhaust sealing paste upstream of the CAT.

• Always refer to instructions and replace heatshields.

If you are unsure about replacing a CAT don’t do it!