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 communications
10Original wording in English
VOLKSWAGEN
Reported code forms P0456
Customer states noise from heat shield Customer states MIL-on with P0496 Customer states MIL-on with P1429 and/or P0556 Customer states MIL-on with P0197 Customer states MIL-on with P0116 MIL-on P0456 Customer states…
VOLKSWAGEN
Reported code forms P0456
Customer states noise from heat shield Customer states MIL-on with P0496 Customer states MIL-on with P1429 and/or P1556 Customer states MIL-on with P0197 Customer states MIL-on with P0116 MIL-on P0456 Customer states…
VOLKSWAGEN
Reported code forms P0456
Customer states noise from heat shield Customer states MIL-on with P0496 Customer states MIL-on with P1558 Customer states MIL-on with P0116 MIL-on P0456 Customer states the sunshade is binding/tearing/separating The…
VOLKSWAGEN
Reported code forms P0456
Customer states noise from heat shield Customer states MIL-on with P0496 MIL-on P0456 Customer states the sunshade is binding/tearing/separating The front window regulator(s) exhibiting noise, shutter, binding, or is…
VOLKSWAGEN
Reported code forms P0456
Customer states noise from heat shield Customer states there is a rattle from beneath the vehicle Customer states MIL-on with P0496 MIL-on P0456 Customer states the sunshade is binding/tearing/separating The front…
VOLKSWAGEN
Reported code forms P0456
Customer states noise from heat shield Customer states there is a rattle from beneath the vehicle Customer states MIL-on with P0496 MIL-on P0456 Customer states the sunshade is binding/tearing/separating The front…
Check vehicle applicability
1A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
| Make | Model | Model year |
|---|---|---|
| Volkswagen | PASSAT | 2017 |
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.