Warning lights, diagnostics, DPF and carbon cleaning

The light, the code, and what it means

A warning light on the dash tells you almost nothing on its own, which is why people find it so unsettling. An amber engine light can be a loose filler cap or a failing sensor or the start of something expensive, and the only way to know is to plug a proper diagnostic tool into the car and read what it has recorded. Andy does that on your driveway. The tool gives a code, and the code points at a system: fuelling, ignition, emissions, the diesel particulate filter, the turbo, a sensor that is reading wrong or not at all. That is where the plain explanation comes in, because a code is not a diagnosis. A DPF code on a diesel that only ever does short trips to school and back usually means the filter is blocked with soot it never got hot enough to burn off, and that is a cleaning job, not a new filter. An oxygen sensor code can be the sensor or the wiring to it. Andy tells you what the code says, what he thinks is behind it, and what it would cost to put right, and he clears the light only when the fault is fixed, not to make it go away for a week. Carbon cleaning, which strips the build-up from the inlet and the injectors on an engine that has been run gently for a long time, is the other half of the diagnostics work, and he will say honestly whether your car needs it.

Warning lights

Engine management, DPF, glow plug, ABS, airbag, battery, oil pressure. Each one is read with a proper tool, and the code explained before any work is priced.

DPF cleaning

A blocked diesel particulate filter from short trips and low speeds. Cleaned rather than replaced where it can be, and a straight word about how you drive the car afterwards so it does not block again.

Carbon cleaning

Build-up in the inlet and on the injectors from a long stretch of gentle driving. Cleaned to restore how the engine breathes. Andy will tell you whether your car needs it or whether the money is better spent elsewhere.