Ask an expert

Recently the catalytic converter fitted to my 2002 Honda Odyssey failed and was temporarily removed by my mechanic.

I have the option of replacing the converter or installing a resonator, the latter being the cheaper option.

Will the car still be compliant if the catalytic convertor is removed and will it continue to be compliant if the regulations change in the future.

And would fitting a resonator be regarded as modifying the vehicle and likely void my extended mechanical warranty insurance.

Lynn.

A vehicle will be rejected during a Warrant of Fitness inspection if the catalytic converter has been removed and the vehicle fits into the criteria set out below (taken from the Vehicle Inspection Requirements Manual).

Reasons for rejection;
A vehicle (other than group L vehicle or a class MA or MC motorsport vehicle with a valid motorsport authority card) that was first registered in New Zealand on or after 1 May 2010 and manufactured from 1 January 1990 has a catalytic converter removed where there is evidence that one was originally fitted, and there is no written evidence issued by a TSDA that the vehicle passed a prescribed metered emissions test in this condition

If your vehicle was first registered in NZ prior to 1 May 2010, it is exempt from this rule and provided the exhaust system meets the objective noise level test and does not leak, then it will pass a Warrant of Fitness inspection.

I can understand the reasons for removing the catalytic converter (normally high cost) although it does allow the vehicle to produce higher tail pipe emissions which is not desirable for the environment.

Any car fitted with a catalytic convertor will also have what is called an oxygen sensor fitted into the exhaust system just forward of the converter.

It is very important this sensor is left in place as it is connected to the engine management system and to the dash engine warning light.

If it is disconnected the dash warning light will stay on which is a definite WoF reject.

The oxygen sensor is there to protect the convertor by monitoring the air/fuel mixture in the exhaust system and will continue to operate regardless of whether the catalytic convertor is fitted or not.

It would definitely pay to check with your warranty insurance under-writer and ask whether this change has any affect on your policy.

They may also mention the oxygen sensor issue.