Diagnostics

Fault finding & repair

Warning light, limp mode, a DPF that will not regenerate, an EGR or AdBlue fault: found with live data and fixed properly.

What is the car doing?

Pick the warning.

What it usually means, what we check first, and a booking that already says it.

Usually: A fault the engine's control unit has stored: a sensor, a misfire, a boost or a fuelling problem.
What we check: Every code read, then the live data behind it, so the repair fixes the cause and not the light.

Usually: The control unit has cut power to protect the engine: often boost (a split hose, a sticking actuator), a sensor or the DPF.
What we check: Boost and sensor readings on a test drive, logged, then the part that is actually at fault.

Usually: The particulate filter is filling faster than it cleans itself: short journeys, failed regenerations, a sensor or an injector.
What we check: Soot load, pressure readings and why it is not regenerating; a forced regeneration or a clean where that is the right fix.

Usually: A valve sticking with carbon, a cooler, or the sensor that reads its position.
What we check: Where the valve is against where it is told to be; cleaned or replaced, and the reason it clogged.

Usually: A fault in the SCR system: the pump, the heater, a NOx sensor or the fluid itself. When the count reaches zero the engine will not restart.
What we check: The SCR faults read live; pump, heater and sensors tested before any part is changed.

Usually: A boost leak, a blocked intake or a tired sensor the car has not flagged yet.
What we check: A logged run against what the engine should make; on our rolling road when the numbers matter.

The law

A road car in the UK must keep its emissions equipment working: removing a DPF, EGR or AdBlue system is an MOT fail and against the law on the road.

So we fix them. Software changes to emissions systems are for competition and off-road vehicles only, and we ask what the vehicle is used for.

MMT Performance · Nottingham

Open now · until 21:00