Warning Light On? Find Out What’s Actually Wrong.
£150. No repair booked, no obligation. If you go on to book the DPF clean with us, the £150 comes off.
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A full 12-point diagnostic check at your home or work, and a written report telling you what is really wrong, what it will cost, and what you can safely ignore.
- Every control unit scanned, not just the one that lit up
- Live data while the engine runs, plus hands on the car
- Plain-English written report you can take anywhere
A Warning Light Tells You Almost Nothing
It points at an area. It does not tell you the cause.
Plenty of garages read the code, replace the part it names, and hope. Sometimes that works. Often it does not, because the code was a symptom, and now you have paid for a part you never needed and the light is still on.
We do it the other way round. Find the actual cause first, then tell you what needs doing. Sometimes the answer is that nothing does.
What £150 Actually Buys
The same check we run on every job, whatever the customer booked. Twelve points, start to finish.
- Full system scan. Every control unit, not just the one that triggered the light. Live, stored and recently cleared faults where the car gives them up.
- Live running data. What the engine is actually doing while it runs, not just what it wrote down earlier.
- Airflow. How much air the engine really draws against what it thinks it draws. Wrong here changes the fuelling, and that is where soot comes from.
- DPF pressure sensor and its pipework. A failed sensor reports a blockage that was never there, or misses one that is.
- Exhaust backpressure. How restricted the filter really is, in numbers.
- EGR valve, live actuator test. Driven open and closed through the tool and watched in real time. Plenty of condemned valves pass this.
- EGR cooler and thermostat. A fouled cooler mimics a dead valve. A thermostat stuck open means the engine never gets hot enough to clean itself.
- Emissions sensors and AdBlue dosing. NOx sensors upstream and downstream, compared. On AdBlue cars, whether fluid is actually being injected.
- Regeneration history and exhaust temperatures. Why the car’s own self-clean keeps failing.
- Fuelling and turbo. Injector behaviour in the live data, and a check for oil getting into the exhaust.
- Hands on the car. Pipework and hoses, turbo pipes especially, checked physically for splits and tears. A split turbo pipe will not always throw a code. This is the part a plug-in code reader cannot do.
- Battery, charging and wiring. Emissions sensors are sensitive to low voltage, and a weak battery can permanently kill one.
You Get It in Writing
Not a verbal "it’s probably the sensor mate" on the driveway. A written report: what we found, what it means, what it costs to fix, and what is not worth touching.
Take it wherever you like. Your own garage, the dealer, the seller you are buying from. It is your report. We are not going to be offended.
That is deliberate. A diagnosis you can act on independently is worth more than one that only makes sense if we do the work.
When This Is the Right Call
- A warning light with no obvious cause. Nobody has explained it and you would rather know before you spend.
- A second opinion. Another garage has quoted for a repair and you want to know if it is the real fault.
- A car that doesn’t feel right. Down on power, drinking fuel, running rough, nothing conclusive.
- Before a long trip. Peace of mind, and cheaper than a recovery truck.
- Before you buy a used diesel. Especially anything with a DPF, EGR or AdBlue system. Cleared fault codes do not always stay hidden.
Why Us
- 30 years under the bonnet. Diesel engines and emissions systems, all day.
- Dealer-level tools. Autel diagnostic equipment, live data, actuator testing.
- We come to you. Home, work or roadside, anywhere in our patch. By appointment, so you get a slot rather than a wait.
- Fully insured.
- Straight answers. If it is something simple, we say so. We are not here to invent problems.
£150, All In
The full 12-point check, at your location, with a written report.
£150
Diagnostic health check
Credited against the repair.
Book the DPF clean with us afterwards and the £150 comes off, so you are not paying twice to find out and then fix it.
No obligation to book anything. If the report says go elsewhere, go elsewhere.
Related Work
Some of what the check turns up most often:
- EGR faults: a new valve often does not fix it, because the cooler or thermostat was the real cause
- AdBlue and SCR warnings: a full tank does not clear a sensor fault
- NOx sensor faults: often killed by an electrical problem, and no amount of code-clearing brings one back
- Blocked DPF: the most common outcome, and the one we clean on site
We Come to You
Based in Watford, covering Hertfordshire, Bedfordshire, Buckinghamshire, Middlesex and North West London, out to Milton Keynes, Oxford, Reading, Guildford and Cambridge.
Home, work or roadside. We work by appointment, so you get a booked slot rather than a wait.
Not sure if you’re in range? Send your postcode and we’ll confirm.
Book Your Diagnostic
Send the details and we’ll come back to you.