Catalytic converters
Check anti-pollution system: what it means and what to do
Check anti-pollution system or anti-pollution fault? What it means on Renault, Dacia, Peugeot and Citroën, what to do, and when the cat or DPF is to blame.
Blog
Practical articles on catalytic converters, DPFs and GPFs, MOT emissions and choosing the right part for your vehicle.
Catalytic converters
P0420 code: catalyst efficiency below threshold
P0420 means catalyst system efficiency below threshold, bank 1. What sets it, what to check before replacing the catalytic converter, and the MOT rules.
DPFs and GPFs
DPF fault codes P2463, P2002, P242F, P2453 explained
What the DPF fault codes P2463, P2002, P242F and P2453 mean, what a garage should check first, and when the filter itself needs replacing.
Catalytic converters
What does homologated mean on a catalytic converter or DPF?
Homologated means type approved. When UK law requires a homologated catalytic converter or DPF, what the MOT checks and how to tell if a part qualifies.
Catalytic converters
Failed your MOT on emissions? What to do next
Why vehicles fail the MOT emissions test, what CO, HC, lambda and smoke readings point to, and what to fix before buying a catalytic converter or DPF.
Theft and security
Catalytic converter stolen? What to do next
A sudden roar when you start the engine usually means the catalytic converter has been stolen. What to do next, and how to stop it happening again.
DPFs and GPFs
What is a GPF? The petrol DPF explained
A GPF (petrol particulate filter) is the petrol version of a DPF: which petrol vehicles have one, the warning lights, and whether it can be removed.
Buying guides
How much does a replacement catalytic converter or DPF cost?
Replacement catalytic converter and DPF prices for popular vehicles, from our own catalogue, and what makes the price go up or down.
Looking for the basics? Our Help & Advice guides cover how catalytic converters and DPFs work, fitting, the law and warranty.