My 2006 S-type with 120,000mile and 2.7 diesel engine (hope that doesn't make anyone bristle with rage) has an odd little fault: Now and again it goes into "restricted performance" plus amber MIL light 'on'. Two different analysers and two different people find there are no DTCs showing. I can get rid of the MIL light by revving the engine after startup to 3000rpm. for 10 seconds while still parked. Then it stays off until next time.
In the back of my mind I'm wondering about that carbon afterburner (DPF I think) because I'm a very sedate driver nowadays. The exhaust pipes stick out straight, no downward curve. Is this likely to be the cause of this funny little fault?
Leedsman.