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An aftermarket catalytic converter costs roughly €200-600 fitted, the original can exceed €1,500 on some models. Before replacing it, however, it must be verified that it really is the problem.

Code P0420 is not enough

The catalyst efficiency below threshold fault can be due to:

• Rear lambda sensor lazy or failed (much lower cost)
• Exhaust leaks before or between the sensors
• Prolonged rich mixture due to injectors or MAF sensor
• Oil consumption poisoning the catalytic converter

Replacing the catalytic converter without having ruled out these causes often means finding the same fault a few weeks later, with a new component already compromised.

How it is checked before spending

• Real-time comparison of the two lambda sensor signals
• Measuring exhaust back-pressure if clogging is suspected
• Exhaust leak test
• Reading the fuel corrections

Original or aftermarket

A quality aftermarket unit with valid type approval is a legitimate and much cheaper choice. Beware of products without approval: besides not being permitted, they often trigger the fault again due to insufficient efficiency.

The figures given are indicative market ranges, useful as a guide: the actual cost depends on model, engine, chosen parts and labour hours. An exact quote requires the vehicle registration.

Tailored quote

Before quoting we check what is really needed: an accurate diagnosis often avoids an expensive replacement. MasterTuning centres throughout Italy.

Request a quote stating model, engine and symptom.

Frequently asked questions

How much does it cost to change the catalytic converter?

Roughly €200-600 with an approved aftermarket part; the original can exceed €1,500 on some models.

Does code P0420 mean the catalytic converter needs changing?

Not necessarily: it can be due to the rear lambda sensor, exhaust leaks or a rich mixture. These must be ruled out first.

Is an aftermarket catalytic converter OK?

Yes, if it is type-approved and of good quality. Non-approved products are not permitted and often trigger the fault again.