p0420
Moderate
Chrysler · Minivans & Sedans
Catalyst System Efficiency Below Threshold (Bank 1)
Quick Answer
Error code P0420 on your Chrysler Minivans & Sedans means: Catalyst System Efficiency Below Threshold (Bank 1). This is usually fixable — see the step-by-step guide below.
Affected Models
Applies to all models
Likely Causes
How to Fix It
1
Check oxygen sensor signals before and after catalyst
2
Inspect catalytic converter for damage or clogging
3
Monitor exhaust gas temperature
4
Test fuel system and ignition 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 sensors
Exhaust gaskets
Engine sealant
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