What does this code mean?
P0442 describes a small leak, P0455 a large leak and P0456 a very small leak. Check the correct fuel-cap seal where fitted, hoses, valves and the manufacturer's leak-test procedure. A loose cap is one possibility, not the only cause. Do not use compressed air or improvised flame tests around fuel vapour.
Sources and interpretation [1]
A code identifies a detected condition, not a part that must automatically be replaced.
Manufacturer wording
Source wording can vary by vehicle and suffix. It is shown as written, not as a universal diagnosis.
P0456very small EVAP leakP045600very small EVAP leakP045600EVAP system leak detected NVLD (very small leak)) - Repair AuthorizationManufacturer communications
35Original wording in English
AUDI
Reported code forms P045600
This bulletin provides information when the fuel tank cap seal is leaking; DTC P044200, P045600 and/ or P00EF00 in stored in the ECM.
AUDI
Reported code forms P045600
This bulletin provides information when the fuel tank cap seal is leaking; DTC P044200, P045600 and/ or P00EF00 in stored in the ECM.
AUDI
Reported code forms P045600
This TSB provides information when the fuel tank cap seal is leaking, DTC P044200, P045600, and/or P00EF00 stored in ECM.
AUDI
Reported code forms P045600
This bulletin provides instructions for when the MIL is on and DTC P044200 and/or P045600 is stored in the ECM.
AUDI
Reported code forms P045600
If DTC P044200 or P045600 are present, the GX36 may need to be replaced.
AUDI
Reported code forms P045600
This bulletin advises to replace the EVAP LD Pump if DTC P044200 or DTC P045600 are present under specific circumstances.
Check vehicle applicability
16A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
| Make | Model | Model year |
|---|---|---|
| Audi | A8 | 2026 |
| Audi | A8 | 2025 |
| Audi | A8 | 2024 |
| Audi | A8 | 2023 |
| Audi | A8 | 2022 |
| Audi | A8 | 2021 |
| Audi | A8 | 2020 |
| Audi | A8 | 2019 |
| Audi | A8 | 2018 |
| Audi | A8 | 2016 |
| Audi | A8 | 2015 |
| Audi | A8 | 2014 |
Historical records · 1 · Historical vehicle association; OBD-II compatibility is not established by this record.
Before replacing a part
Record codes and freeze-frame data. Check battery condition, related codes and visible wiring or hose damage. Follow the vehicle's diagnostic procedure and test results before replacing parts.
Sources and interpretation
These explanations are editorial summaries of the linked manufacturer material. PDF page numbers count from the first file page. Original publications are in English; translations are reference aids. A cited edition is not a claim that it is the manufacturer's latest instruction.
- 2024–2025 MY OBD System Operation Summary for Gasoline Engines ↗
Ford Motor Company · PDF page(s) 13, 14 ·
Source check date · 2026-10-27
Can I keep driving?
A code alone cannot establish whether driving is safe. A flashing malfunction light, severe shaking, overheating, oil-pressure warning or loss of braking or steering needs prompt attention. Stop in a safe place and seek assistance when control or engine safety is affected. Follow the vehicle handbook.