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
6Original wording in English
BUICK, CADILLAC, CHEVROLET, GEO, GMC
Reported code forms P0455
This service bulletin provides diagnostic tips/steps on testing for possible EVAP leaks in the system to correct a customer concern of an MIL Illuminated with DTCs P0442 and/or P0455 Set.
BUICK, CADILLAC, CHEVROLET, GMC
Reported code forms P0455
This service bulletin provides diagnostic tips/steps on testing for possible EVAP leaks in the system to correct a customer concern of an MIL Illuminated with DTCs P0442 and/or P0455 Set.
CADILLAC, CHEVROLET, GMC
Reported code forms P0455
Fuel Odor During Fuel Filling or During Idle, Possible P0442 or P0455 DTCs Set
CADILLAC, CHEVROLET, GMC
Reported code forms P0455
Fuel Odor During Fuel Filling or During Idle, Possible P0442 or P0455 DTC SET
CADILLAC, CHEVROLET, GMC
Reported code forms P0455
Fuel Odor During Fuel Filling or During Idle, Possible P0442 or P0455 DTCs Set Some customers may comment on a strong fuel odor during fuel filling or during vehicle idle. Cause This may be caused by the fracture or…
CADILLAC, CHEVROLET, GMC
Reported code forms P0455
DIAGNOSTIC INFORMATION ON MALFUNCTION INDICATOR LAMP (MIL) ILLUMINATED WITH DTCS P0442,P0446, P0451, P0452, P0453, P0454, P0455 AND REPLACEMENT OF FUEL TANK PRESSURE (FTP) SENSOR/MODULE. *PE
Check vehicle applicability
24A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
| Make | Model | Model year |
|---|---|---|
| Cadillac | ESCALADE | 2023 |
| Cadillac | ESCALADE | 2022 |
| Cadillac | ESCALADE | 2021 |
| Cadillac | ESCALADE | 2020 |
| Cadillac | ESCALADE | 2019 |
| Cadillac | ESCALADE | 2018 |
| Cadillac | ESCALADE | 2017 |
| Cadillac | ESCALADE | 2016 |
| Cadillac | ESCALADE | 2015 |
| Cadillac | ESCALADE | 2014 |
| Cadillac | ESCALADE | 2013 |
| Cadillac | ESCALADE | 2012 |
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) 11, 12 ·
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.