1. Manifold / Primary Converter (close to engine)*
Harmful gas from engine What converter does Becomes
**Carbon Monoxide (CO)** - poisonous Oxidation Carbon Dioxide (CO2)
**Hydrocarbons (HC)** - unburnt petrol Oxidation CO2 + Water (H2O)
**Nitrogen Oxides (NOx)** - causes smog/acid rain Reduction Nitrogen (N2) + Oxygen (O2)
First one catches 70-80% of pollution when the engine is cold/hot.Second one cleans what’s left and helps the ECU check if the first one is working — that’s why you have 2 oxygen sensors.
If one fails, you get:
- P0420 / P0430 check engine
- Loss of power (when clogged)
- High fuel consumption
- Loud noise and strong fuel smell (when removed)
Do you want me to explain how mechanics in Accra test if yours is blocked vs. empty?