Diagnostics Doctor

Q This is not specifically a diagnostics problem, but it needs your expertise. I have read in CM about problems that arise if you switch off the engine while the diesel particulate filter (DPF) is regenerating. Is there a way of knowing when a regen is taking place on an Audi 3.0 TDI to avoid this happening? The first is my 2011 Audi A7 (engine code CLAB) and the second is my wife’s 2014 Q5 (engine code CDUC). I was thinking of attaching a bulb or LED to a live wire which triggers the DPF regen actions. Have you any idea where I should start looking? Shabaz A You shouldn’t need to go to such lengths as both of your Audis are fitted with a built-in warning system for the DPF. When the vehicles begin the regeneration process, the warning lamp on the dash will illuminate, displaying the message: ‘Particle filter see owner’s manual’. An audible warning will also sound to alert the driver. When this occurs – which should only be when the engine is at operating temperature – you need to drive the vehicle at a minimum speed of 40mph for at least 15 minutes, ensuring the engine speed remains at approximately 2000rpm. This can be done by using fourth gear if the car is a manual or by selecting ‘Sport’ in automatics. The warning lamp and message will go out once the regeneration has been completed.

A forced regeneration can be carried out using diagnostic equipment, so if the warning light and message do not clear, this option should be used.