Mercedes Diagnostics London | Xentry Fault Code Reading

Mercedes Diagnostics in London (Xentry / Star)

We diagnose Mercedes faults using Xentry / Star — the genuine Mercedes-Benz diagnostic system — to read every control unit in your car, identify the root cause of warning lights, limp mode or electrical issues, and quote you on fixing it the same day in most cases.

Price: From £85 inc. VAT. Credited against any repair. Typical time: 1–3 hours

A generic OBD2 scanner barely scratches the surface of a modern Mercedes. These cars have 40+ control units communicating over multiple CAN buses, and most live data and fault codes are only accessible through Xentry / Star — the same system used in the main dealer network. If you want to know exactly what is wrong with your Mercedes, that is what you need.

What Xentry / Star gives us

Full access to every control unit, live data streams, guided fault-finding trees, component actuations (we can trigger an injector or a valve on demand), SCN coding and online programming where needed. If the fault can be read electronically, we can read it.

Same-day fault-finding

For most warning lights — engine light, ESP, airbag, ABS, transmission, AdBlue — we can have the root cause identified within a couple of hours and give you a fixed-price quote to repair it the same day.

Diagnostics is not guesswork

We do not replace parts hoping the problem goes away. Every repair we recommend is backed by a fault code, live data, or a component test. That is the difference between a Mercedes specialist and a general garage.

What's included

Full Xentry / Star fault code scan across every ECU
Live data analysis
Written fault report
Fixed-price repair quote
Diagnostics charge credited against any repair

Common symptoms we see

Check engine light (MIL) illuminated
Limp mode / reduced power
AdBlue / SCR warnings
Airbag / SRS warning
Intermittent electrical faults
Transmission slipping or shuddering

Frequently asked questions

How much do Mercedes diagnostics cost?

Our standard diagnostic charge is £85 inc. VAT, which includes a full Xentry / Star scan across every control unit, live data analysis and a written report. We credit the charge against any repair we carry out.

Is a generic OBD2 scan the same as Xentry diagnostics?

No. An OBD2 scanner only reads emissions-related faults. A modern Mercedes has 40+ control units. Xentry / Star reads all of them, runs live data, actuates components on demand and does SCN coding — the same as a main dealer.

Is a Mercedes warning light always serious?

Not always, but they should never be ignored. Yellow warnings typically mean "investigate soon" and red warnings mean "stop the car safely". We will read the fault codes and tell you plainly how urgent it is.

Do I get the diagnostic fee back if I go ahead with the repair?

Yes. If we carry out the repair we have quoted, the £85 diagnostic fee is credited against the invoice.