Electronic throttle and pedal: P2119, P2122, P2138, P2110
Pedal to the floor and the car barely moves, refusing to go past two thousand rpm. That is what electronic throttle protection looks like — and nine times out of ten the engine is not to blame, dirt or a single wire is.
If the car will not pick up revs and a P21xx code is on the list, you already know the main thing: the unit is deliberately refusing to open the throttle. It has not broken; it has stopped trusting the data.
Why it is built this way
There is no cable from the pedal to the throttle on a modern car. The pedal is two position sensors, the throttle body is a motor plus two more sensors. The unit reads the pedal, decides how much air to give, and opens the flap itself.
There are deliberately two sensors in each place, and they read differently: one rises from 0.5 to 4.5 V, the other mirrors it. Agreement by the formula means both are intact. The moment they diverge, the unit must assume the worst: the flap could open on its own.
Hence limp mode — the only safe answer to «I do not know what the driver wants».
What each code means
P2138 — the pedal sensors disagree. The most common and the most underrated: the pedal is the part that gets coffee spilled on it, gets washed and gets kicked. The cause is nearly always the connector under the mat, not the control unit.
P2122, P2123, P2127, P2128 — low and high signal from the first and second pedal sensor. Now it is a specific wire.
P2119 — the throttle body sticks. The flap does not go where it is asked. In the vast majority of cases this is carbon on the edge of the flap, not a dead motor.
P2102, P2103 — the drive motor circuit.
P2110 — revs forcibly limited. This is not a fault of its own but an announcement: «I am already in protection». Look for the code standing next to it.
P0221 — the second throttle position sensor out of range; a relative of P0121–P0123, covered in the article on the throttle position sensor.
A two-minute check in the app
Open throttle position and press the pedal slowly from zero to the floor, watching the number.
On a healthy car it grows smoothly and without dropouts: roughly from 12–18 % with the pedal released to 80–95 % at the floor. The exact ends differ from car to car; what matters is the smoothness, not the figure.
What shows up immediately:
- drops to zero mid-travel — the sensor track is worn. A classic on cars over ten years old;
- does not move at all — the circuit or the motor;
- jumps in steps — a poor contact in the connector;
- stops at 30–40 % with the pedal on the floor — you are in protection, and P2110 confirms it.
The second reading is calculated load. In protection it will not rise above 40–50 % however hard you press: the unit physically will not let the engine load up. The two readings agreeing is what tells protection from plain loss of power, which has a dozen other causes.
What to do
- Inspect the pedal connector — it lives under the driver's mat and suffers from water and shoes. That is the first place to look, not the last.
- Clean the throttle body if P2119 is present. Carbon on the flap edge is the most common cause of sticking, and cleaning costs pennies.
- Take a freeze frame — a code while pulling away and a code on the motorway mean different things.
- Check the power supply. A sagging voltage confuses both sensors at once, and then charging codes sit alongside — see charging.
- After cleaning many cars need the throttle relearned; without it the idle wanders even though the fault itself is gone.
⚠️ Driving with P2138 in limp mode is fine exactly as far as the workshop. While the pedal sensors disagree the car does not understand what you want from it — and overtaking needs an answer to the throttle.
