P0422 — Main Catalyst Efficiency Below Threshold (Bank 1)

OA fault code doesn’t yet mean the unit or sensor itself is faulty: often it’s the plug and connector leading to it.

Possible causes

• The catalytic converter is burned out or clogged
• Rear O2 sensor
• Exhaust leak before the sensor
• Misfires in the past

What you can do yourself

1. The car pulls as usual — you can keep driving.
2. Weak pull and the engine “chokes” uphill — the catalyst is clogged, see a mechanic right away.

Find the part on Kaspi ShopBefore buying, check the part number or match the part by VIN in the Kaspi “Garage”.

Check how the second O2 sensor works on the “Sensors” tab.

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The explanation comes from the error code reference in the AvtoElektrik PRO app.