Emission System Problem
Honda Vehicle
Severity: ModerateWhat Does This Error Mean?
The Honda Emission System Problem message means a fault has been detected in the emissions control system. This typically accompanies the check engine light and is stored as an OBD-II code. Common causes include the EVAP system, oxygen sensors, or catalytic converter. Get the code read to identify the specific fault.
Affected Models
- Honda Civic (2006 onwards)
- Honda CR-V (2007 onwards)
- Honda Accord (2008 onwards)
- Honda HR-V
- Honda Pilot
Common Causes
- Fuel cap loose, damaged, or missing — most common cause, triggers EVAP code
- EVAP canister or purge valve fault — emissions vapour system not functioning
- Oxygen sensor degraded — engine running rich or lean
- Catalytic converter efficiency below EPA threshold (P0420)
- EGR (Exhaust Gas Recirculation) valve stuck or fouled — common on Honda Accord 4-cylinders
- Secondary Air Injection system fault on applicable models
How to Fix It
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Check and retighten the fuel cap.
This is free to fix and causes a large percentage of Honda emission system warnings. Remove the cap, check the rubber seal is intact, and refit until it clicks. Drive for 3 days to see if the message clears.
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Get the OBD-II code read.
The code pinpoints which emissions component has faulted. Free at any auto parts store. P0455 = large EVAP leak (likely the cap). P0420 = catalytic converter. P0141 = rear oxygen sensor.
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Do not confuse this with the Emissions Recall.
Honda has issued emissions recalls on several models (Accord, Pilot, Civic) over the years. Check recall status using your VIN at the NHTSA website — a recall fix may be available at no cost at a Honda dealer.
Frequently Asked Questions
Is the Honda Emission System Problem serious?
It depends on the cause. A loose fuel cap is trivial — just tighten it. A catalytic converter fault or EVAP system leak is more involved but not immediately dangerous. Drive carefully and get it diagnosed within a week. If the check engine light is also flashing, that is urgent — reduce speed and get to a workshop.
Will the Emission System Problem message clear itself?
If the fault is resolved (for example, a fuel cap that was loose and is now tight), the message will clear automatically after 3-5 successful drive cycles. If the underlying issue is not fixed, the message will remain permanently.