PID 47%

Throttle position B

The position of the second throttle. A second throttle belongs to V engines — one per bank — and to cars with split intake control. The meaning is the same as PID 11, but you must read the PAIR: on a healthy engine both move together, and a gap means one of them is sticking, at which point the engine pulls unevenly as if half the cylinders were working at half strength. PID 4C is the command given to both.

What is normal

It must move in step with the main one. If they disagree, that is a throttle fault and the engine will go into limp mode.

These figures hold for most cars, but the maker has the last word: some engines run hotter or idle higher by design.

Codes about this parameter

P0121Throttle position sensor A circuit range/performance P0122Throttle position sensor A circuit low input P0123Throttle position sensor A circuit high input

Codes behind this reading

If the value is out of range, the unit usually says so with one of these codes.

P2100Throttle actuator — circuit open P2101Throttle actuator — range or performance fault

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.

What the app does