⚠️ Mercedes-Benz manufacturer position
Mercedes-Benz WIS specifies fuel pump module access (often under rear seat) or tank removal per body style. Misfuel excluded from warranty.
Vehicle information
| Make | Mercedes-Benz |
|---|---|
| Model | A-Class |
| Market status | Sold new in Great Britain — W177 (2018–present) |
| Body styles | Hatchback, Saloon (A-Class Sedan) |
| Generations | W176 (2012–2018), W177 (2018–present UK) |
| Engine options | Petrol: 1.3–2.0 L petrol (M282/M260) on UK A-Class Diesel: 2.0 L diesel (OM654) on UK diesel A-Class |
| Fuel tank capacity | Approximately 43–50 litres — consult WIS for wheelbase |
| Fuel system | Petrol direct injection; diesel OM654 common-rail with HP pump |
| Access method | Under rear seat module access on many UK A-Class hatchbacks |
| Anti-siphon | Yes — Mercedes Easy Fuel style restrictor on many UK cars |
| Service portal | Mercedes-Benz WIS / XENTRY Workshop (authorised dealers) |
Misfuel risk Moderate
Petrol and diesel variants share similar filler arrangements; mis-fuelling most often affects diesel models where petrol causes immediate high-pressure system risk.
If the engine was not started
Drain, replace filter, refill, prime low-pressure circuit via XENTRY routines.
If the engine was started
Diesel A-Class with petrol: HP pump, rail, injector inspection mandatory.
Access procedure
- Disconnect the negative battery terminal and relieve fuel system pressure per OEM procedure.
- Access the in-tank fuel pump module via the manufacturer-specified route (access panel or tank lowering).
- Drain contaminated fuel using approved recovery equipment into suitable containers for hazardous waste duty of care.
- Inspect the tank, sender unit, and lines; replace the fuel filter and any contaminated flexible lines as required.
- Reassemble, refill with the correct fuel grade, prime the low-pressure circuit, and check for leaks before start.
- If the engine was run on wrong fuel, follow OEM guidance for high-pressure pump, rail, and injector inspection before restart.
Related models
- B-Class
- CLA
Frequently asked questions
What should I do if I put petrol in my Mercedes-Benz A-Class diesel?
Do not start the engine. Arrange OEM-method tank fuel extraction and hazardous waste disposal under UK duty of care. A GBIFDA-certified technician can document the procedure for insurers.
Does Mercedes-Benz warranty cover misfuel on a A-Class?
Manufacturer warranties typically exclude wrong fuel as misuse. Expect out-of-pocket or insurance-funded repair.
Can I siphon fuel from a Mercedes-Benz A-Class?
UK Mercedes-Benz models usually have anti-siphon filler necks; OEM information specifies pump-module or tank removal instead.
When are injectors replaced after misfuel on a A-Class?
If the engine ran on contaminated diesel, injectors and HP pump are inspected or replaced per Mercedes-Benz diagnostics; not always required if caught before start.
Need professional misfuel recovery?
Find a certified operator or read consumer guidance for your next steps.
Find an operator Consumer guidance