Greetings to all I present to you a Tata Safari 2.2 year 2009 with indicator light for engine failure on ( and the red check) with the error p0400...On the car I have carried out various checks including : egr (pneumatic) does not lose and in its operation seems to run fine, all pipes changed, a solenoid valve ok, depression before\after solenoid valve ok, pipe egr free I disassembled and cleaned it for good, mass air flow sensor functioning properly, waste recovery ok...in the diagnosis egr works occasionally there are moments in which the operation stops responding....I put the oscilloscope in fact I have a loss of signal in the moment in which the diagnosis I do not have the operation...I thought to exclude the egr, but with kess I do not have the possibility to do the reading...what escapes me ?Thanks