OBD-II code family
EVAP Purge and Vent Control Circuit Faults (9 codes)
9 related fault descriptions. Use each full code and the exact vehicle service information to identify its circuit, monitored condition, and required tests.
Codes in this family
This is the complete published member list for this guide. Each code retains its own page; shared diagnostic context does not mean that every member has the same test or repair.
- P0443Evaporative Emission System Purge Control Valve Circuit
- P0444Evaporative Emission System Purge Control Valve Circuit Open
- P0445Evaporative Emission System Purge Control Valve Circuit Shorted
- P0446Evaporative Emission System Vent Control Circuit Malfunction
- P0447Evaporative Emission System Vent Control Circuit Open
- P0448Evaporative Emission System Vent Control Circuit Shorted
- P0449EVAP Vent Solenoid Control Circuit Malfunction
- P0458Evaporative Emission System Purge Control Valve Circuit Low
- P0459Evaporative Emission System Purge Control Valve Circuit High
What these codes mean
P0443 concerns purge-control circuit context, P0444 an open condition and P0445 a shorted condition. P0458/P0459 distinguish low/high purge-control results. P0446, P0447, P0448 and P0449 concern vent-control circuit, open, shorted and valve/solenoid-control descriptions. The member list preserves each exact title; a control fault is different from proving a vapor leak.
Identify the full DTC, suffix, command state and characteristic the controller evaluates. “High” is not always excessive voltage: Mitsubishi’s covered 2023 DGE P0459 procedure evaluates coil current with purge commanded on. Its P0458 procedure evaluates voltage with command off, including specified monitoring after shutdown. A numerical supply check from another code cannot replace either diagnostic path.
Other examples have their own boundaries. The covered 2022 DG P0443 description and linked diagnosis include electrical and vapor-path checks. Ford’s covered P0443_01/P0446_01 examples use driver-status monitoring. These do not establish identical circuit layouts, default valve positions or measurement rules for every manufacturer.
Companion codes can change the repair path. Infiniti ITB22-042 applies to listed 2021–2023 QX50 and 2022–2023 QX55 vehicles: P0451, P0452, P0454 or P0447 accompanying P0448 selects the pressure-sensor branch. GM 23-NA-073 includes a severe-dust canister/vent-restriction example for listed Silverado/Sierra applications, excluding ZW9. Neither bulletin authorizes a universal valve replacement or retrofit.
Preserve fault records, inspect accessible cooled wiring and have the prescribed supply, return, control and functional checks performed. Do not power an unknown valve directly, bridge control pins or substitute a generic test lamp. Clicking, movement, sealing and flow need distinct checks. Repair the demonstrated fault and verify the relevant monitor; the code cannot establish a safe driving distance.
Identify the circuit on your vehicle
Match the full DTC, reporting module, and any failure-type suffix to the service information for your exact year, make, model, engine, and equipment. An identifier alone does not establish installed hardware count, location, connector pinout, or a universal measurement.
Where the manufacturer publishes its own meaning for this code, that is the one to work from — it describes the actual component on your vehicle, which the generic definition cannot. Keep the generic description for what it is good for: it tells you which subject area the standard assigned the code to, which is useful context when the two appear to disagree. If they do disagree, follow the manufacturer.