p0420
Moderate
Land Rover · SUVs
Catalyst System Efficiency Below Threshold (Bank 1)
Quick Answer
Error code P0420 on your Land Rover SUVs 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
Verify fault with OBD-II scanner
2
Inspect exhaust system for leaks
3
Check oxygen sensor readings pre and post catalyst
4
Test catalytic converter efficiency
5
Replace catalytic converter if efficiency is low
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 sensors
Exhaust gaskets
Oxygen sensor socket
Related Error Codes