1High Likelihood
AdBlue / NOx sensor SCR faults
Engine light, emissions warning, AdBlue message, reduced power, or a restart countdown on the dash.
How to check
Read fault codes with Mercedes-capable diagnostics.
Estimated Repair Cost
£900
Should I buy a 2020 Mercedes-Benz A-Class 1.5 Diesel Automatic W177?
Explore common problems, estimated repair costs and practical checks for the 2020 Mercedes-Benz A-Class 1.5 Diesel Automatic W177. Use this guide to help assess a used car, then unlock a personalised report for the exact vehicle you're considering.
Common problems
2High Likelihood
EGR valve / EGR sensor fouling
Engine light, hesitant pickup, rougher running, flat acceleration or occasional reduced-power mode.
How to check
Pull away from a junction, then build speed smoothly through the mid-range once the engine is warm.
Estimated Repair Cost
£850
3High Likelihood
Panoramic roof drain or routing water ingress
Musty smell, damp carpet, wet headlining, condensation after rain, or unexplained electrical oddities.
How to check
Open the doors after the drive and use your hand around the front and rear floor edges and headlining corners.
Estimated Repair Cost
£900
MOT Failure Rate
Mercedes-Benz A-Class buying questions
Is a 2020 Mercedes-Benz A-Class worth buying?
It can be, but only if the individual car backs it up. For the 2020 Mercedes-Benz A-Class 1.5 Diesel Automatic W177, treat model-level patterns as viewing priorities and let condition, history and inspection evidence decide.
What common problems affect the Mercedes-Benz A-Class (2020)?
The problem cards above list the model-level checks for this guide. Read them as priorities for inspection and paperwork review, not proof that every example will have those faults.
What should I check before buying a Mercedes-Benz A-Class?
Look for evidence, not just assurances: MOT advisories, service history, repair invoices, warning lights, fluid leaks, tyre and brake condition, and how the car behaves on a proper test drive. And of course, look at your personalised Should I Buy This Car? report, outlining a full list of common issues in detail, a personalised road test, a plain-English explanation and a MotorIQ score.
A model guide is useful. A report on its registration is better.
The guide above gives you the model-level pattern. A personalised MotorIQ report checks the registration-specific record and turns it into an ownership view before you commit.
Or enter the vehicle manually