PID 73kPa
Exhaust pressure
Pressure in the exhaust. It rises when the exhaust gets tight: a melted catalyst, a blocked particulate filter, a crushed pipe. The engine then «will not pull at the top» and runs hot. Read it together with the particulate filter temperature (PID 7C) and with boost: a blocked exhaust chokes the turbo well before it manages to set a code.
What is normal
Rising with revs more than usual means the exhaust is furred up: filter, catalyst or a crushed pipe.
These figures hold for most cars, but the maker has the last word: some engines run hotter or idle higher by design.
How it feels behind the wheel
The same fault shows itself in different ways. Each sign below says what to look at in the live data.
The revs are capped and the car will not accelerateThe pedal is flat to the floor but the engine caps out around three thousand and goes no further. The car moves, but sluggishly, and overtaking is impossible. The check light is often on.The car has lost powerThe car moves, but sluggishly: flooring the throttle changes nothing, the revs climb reluctantly. Often the lamp is on as well.
How to see it
In CarScan: the Live data tab, «Start polling». The app asks the car several times per second, draws a graph and remembers the highest and lowest value of the trip.