p0420
Moderate
Jaguar · Sedans & Sports Cars
Catalyst System Efficiency Below Threshold (Bank 1)
Quick Answer
Error code P0420 on your Jaguar Sedans & Sports Cars means: Catalyst System Efficiency Below Threshold (Bank 1). This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
How to Fix It
1
Check exhaust for leaks
2
Test oxygen sensors
3
Inspect catalytic converter
4
Run fuel system cleaner
5
Check engine timing
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
Catalytic converter
Oxygen sensor
Exhaust gasket
Fuel system cleaner
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