Fault codes P0400–P0499
P04xx codes mainly cover: tank venting and fuel vapours, egr valve, diesel particulate filter (dpf). Our list has 100 codes in this range. With most of them you can drive gently, but get the car checked soon. Repairs cost roughly €10–1500, depending on the fault. The most common are P0400, P0401, P0402.
Most common in this range
P0400EGR valve not working properlyP0401Too little gas flowing through the EGR valveP0402Too much gas flowing through the EGR valveP0403Fault in the EGR valve wiringP0404EGR valve isn't where it should beP0405EGR valve position sensor signal too lowP0406EGR valve position sensor signal too highP0411Secondary air pump not delivering enough air
All codes in this range
P0400EGR valve not working properlyP0401Too little gas flowing through the EGR valveP0402Too much gas flowing through the EGR valveP0403Fault in the EGR valve wiringP0404EGR valve isn't where it should beP0405EGR valve position sensor signal too lowP0406EGR valve position sensor signal too highP0407EGR valve: signal or voltage too low ("B")P0408EGR valve: signal or voltage too high ("B")P0409EGR valve: circuit fault ("A")P0410Secondary air system: circuit faultP0411Secondary air pump not delivering enough airP0412Secondary air valve: circuit fault ("A")P0413Secondary air valve: open circuit ("A")P0414Secondary air valve: short circuit ("A")P0415Secondary air valve: circuit fault ("B")P0416Secondary air valve: open circuit ("B")P0417Secondary air valve: short circuit ("B")P0418Secondary air pump relay: circuit fault ("A")P0419Secondary air pump relay: circuit fault ("B")P0420Catalytic converter no longer cleaning properlyP0421Pre-catalyst no longer cleaning properlyP0422Catalytic converter: efficiency too low (main catalyst, bank 1)P0423Catalytic converter: efficiency too low (heated catalyst, bank 1)P0424Catalyst temperature sensor: too low (heated catalyst, bank 1)P0425Catalyst temperature sensor: fault (bank 1, sensor 1)P0426Catalyst temperature sensor: reading or operation not right (bank 1, sensor 1)P0427Catalyst temperature sensor: signal or voltage too low (bank 1, sensor 1)P0428Catalyst temperature sensor: signal or voltage too high (bank 1, sensor 1)P0429Catalyst heater: circuit fault (bank 1)P0430Catalytic converter no longer cleaning properly (bank 2)P0431Catalytic converter: efficiency too low (warm-up catalyst, bank 2)P0432Catalytic converter: efficiency too low (main catalyst, bank 2)P0433Catalytic converter: efficiency too low (heated catalyst, bank 2)P0434Catalyst temperature sensor: too low (heated catalyst, bank 2)P0435Catalyst temperature sensor: circuit fault (bank 2, sensor 1)P0436Catalyst temperature sensor: reading or operation not right (bank 2, sensor 1)P0437Catalyst temperature sensor: signal or voltage too low (bank 2, sensor 1)P0438Catalyst temperature sensor: signal or voltage too high (bank 2, sensor 1)P0439Catalyst heater: circuit fault (bank 2)P0440Fault in the fuel vapour (EVAP) systemP0441Tank purge not working properlyP0442Small leak in the fuel vapour systemP0443Fault in the purge valve wiringP0444EVAP purge valve: open circuitP0445EVAP purge valve: short circuitP0446Charcoal canister vent valve not workingP0447EVAP vent valve: open circuit (vent valve)P0448EVAP vent valve: short circuit (vent valve)P0449Fault in the canister vent valve wiringP0450Fuel tank pressure sensor (EVAP): circuit faultP0451Tank pressure sensor reads wrongP0452Fuel tank pressure sensor (EVAP): signal or voltage too lowP0453Fuel tank pressure sensor (EVAP): signal or voltage too highP0454Fuel tank pressure sensor (EVAP): signal drops out at timesP0455Large leak in the fuel vapour systemP0456Very small leak in the fuel vapour systemP0457Fuel cap loose or missingP0458EVAP purge valve: signal or voltage too lowP0459EVAP purge valve: signal or voltage too highP0460Fuel level sensor: circuit faultP0461Fuel gauge reading is wrongP0462Fuel level sensor: signal or voltage too lowP0463Fuel level sensor: signal or voltage too highP0464Fuel level sensor: signal drops out at timesP0465Fuel vapour system (EVAP): circuit faultP0466Fuel vapour system (EVAP): reading or operation not rightP0467Fuel vapour system (EVAP): signal or voltage too lowP0468Fuel vapour system (EVAP): signal or voltage too highP0469Fuel vapour system (EVAP): signal drops out at timesP0470Exhaust pressure sensor: circuit fault ("A")P0471Exhaust pressure sensor reads wrongP0472Exhaust pressure sensor: signal or voltage too low ("A")P0473Exhaust pressure sensor: signal or voltage too high ("A")P0474Exhaust pressure sensor: signal drops out at times ("A")P0475Exhaust pressure control valve: fault ("A")P0476Exhaust pressure control valve: reading or operation not right ("A")P0477Exhaust pressure control valve: signal or voltage too low ("A")P0478Exhaust pressure control valve: signal or voltage too high ("A")P0479Exhaust pressure control valve: signal drops out at times ("A")P0480Fault in radiator fan controlP0481Radiator fan: circuit fault (no. 2)P0482Radiator fan: circuit fault (no. 3)P0483Radiator fan: circuit fault (plausibility check)P0484Radiator fan: current too highP0485Radiator fan power/ground: circuit faultP0486EGR valve: circuit fault ("B")P0487Electronic throttle: open circuit ("A")P0488Electronic throttle: reading or operation not right ("A")P0489EGR valve: signal or voltage too low ("A")P0490Short circuit in the EGR valve wiringP0491Secondary air system: flow too low (bank 1)P0492Secondary air system: flow too low (bank 2)P0493Radiator fan: too high (fan)P0494Radiator fan: signal or voltage too lowP0495Radiator fan: signal or voltage too highP0496Fuel vapour system (EVAP): incorrect flowP0497Fuel vapour system (EVAP): flow too lowP0498EVAP vent valve: signal or voltage too lowP0499EVAP vent valve: signal or voltage too high
Want a definite answer?
Bring the car to our workshop in Estonia for diagnostics. We read the fault codes, test the sensors and tell you what is wrong. Repair price depends on the work involved, generally €45 per hour.