Fault-code guides

The most common check-engine codes explained. Click a code for details.

• P0420P0420 – Catalyst system efficiency below threshold (Bank 1)
• P0171P0171 – System too lean (Bank 1)
• P0300P0300 – Random/multiple cylinder misfire detected
• P0299P0299 – Turbocharger/supercharger underboost
• P2002P2002 – Diesel particulate filter efficiency below threshold (Bank 1)
• P0401P0401 – Exhaust gas recirculation (EGR) flow insufficient
• P2463P2463 – Diesel particulate filter (DPF) soot accumulation
• P2015P2015 – Intake manifold runner position sensor/switch circuit range/performance (Bank 1)
• P0087P0087 – Fuel rail/system pressure too low
• P0101P0101 – Mass air flow (MAF) circuit range/performance