Symptom hub
Failed Emissions Test: Active Fault vs Monitor Not Ready
A failed inspection is not automatically an EVAP story. Sometimes the car has an active emissions fault. Other times the repair may be finished but one or more monitors never completed after codes were cleared or the drive cycle never matched the test conditions.
Likely related codes
Start your diagnostic path here
P0420 — Catalyst System Efficiency Below Threshold (Bank 1) P0430 — Catalyst System Efficiency Below Threshold (Bank 2) P0455 — EVAP System Leak Detected (Large Leak) P0456 — EVAP System Leak Detected (Very Small Leak) P0401 — Exhaust Gas Recirculation Flow Insufficient Detected P0130 — O2 Sensor Circuit (Bank 1 Sensor 1) P0133 — O2 Sensor Circuit Slow Response (Bank 1 Sensor 1) P0440 — Evaporative Emission Control System Malfunction P0140 — O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 2) P0421 — Warm Up Catalyst Efficiency Below Threshold (Bank 1) P0431 — Warm Up Catalyst Efficiency Below Threshold (Bank 2) P0150 — O2 Sensor Circuit Malfunction (Bank 2 Sensor 1) P0153 — O2 Sensor Circuit Slow Response (Bank 2 Sensor 1) P0154 — O2 Sensor Circuit No Activity Detected (Bank 2 Sensor 1) P2096 — Post Catalyst Fuel Trim System Too Lean (Bank 1) P2098 — Post Catalyst Fuel Trim System Too Lean (Bank 2) P0402 — Exhaust Gas Recirculation Flow Excessive Detected P0410 — Secondary Air Injection System Malfunction P0411 — Secondary Air Injection System Incorrect Flow Detected P0418 — Secondary Air Injection System Relay A Circuit Malfunction P1128 — Closed Loop Fueling Not Achieved Bank 1 P1129 — Closed Loop Fueling Not Achieved Bank 2 P1174 — Fuel Trim Cylinder Balance Bank 1
Connected paths
Brand hubs where this symptom is common
Browse all brand hubs
Built to keep related fixes, symptoms, and hubs one step away.
Connected paths
Guides to read next
Browse all guides
Built to keep related fixes, symptoms, and hubs one step away.
P0420 vs Bad O2 Sensor vs Exhaust Leak: How to Tell Which One Is Actually Setting the StoryRear O2 Sensor Code vs Bad Catalytic Converter: How to Tell Which One Is Actually WrongEVAP Leak Detection Pump vs Vent Valve vs Switching Valve: How to Tell Which EVAP Hardware Is Actually FailingFailed Emissions Test: Active Code vs Monitor Not Ready