A failed accelerator pedal position sensor 2 track inside the pedal assembly, which is the most common cause on high-mileage BMWs.; A short to voltage on the sensor 2 signal wire where the harness rubs against the pedal bracket or passes through the bulkhead.; Corroded or pushed-back pins in the pedal sensor connector, allowing the signal voltage to float high.; Water ingress into the pedal connector or footwell area, often from a blocked sunroof drain or windscreen cowl leak.; A faulty DME internal pull-up circuit on the sensor 2 input, though this is rare compared with pedal and wiring faults.; An intermittent short caused by a chafed harness near the steering column or pedal box after previous dashboard repairs.

DTC codes / BMW codes / P1223

P1223 · BMWPedal Position Sensor 2 High Input

Q: What does code P1223 mean?

Pedal Position Sensor 2 High Input. P1223 on a BMW means the engine control module (DME) has detected a high input voltage on the signal circuit of pedal position sensor 2, which is the second track inside the accelerator pedal assembly. The computer expects this sensor's voltage to rise and fall within a specific range as the pedal moves, and a sustained high reading tells the DME the circuit is shorted to voltage or the sensor has failed.

P1223 on a BMW means the engine control module (DME) has detected a high input voltage on the signal circuit of pedal position sensor 2, which is the second track inside the accelerator pedal assembly. The computer expects this sensor's voltage to rise and fall within a specific range as the pedal moves, and a sustained high reading tells the DME the circuit is shorted to voltage or the sensor has failed.

SystemPowertrain

Code typeBMW specific

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering (injector circuits)

Symptoms you may notice

The check engine light or electronic throttle warning lamp illuminates on the instrument cluster.
The engine may enter limp mode, limiting power and throttle response to a fast idle or low speed.
Acceleration feels flat or unresponsive, with the pedal needing excessive travel to build speed.
The idle may hang high or flare unexpectedly when coming to a stop.
Often no symptoms besides the warning light, especially if sensor 1 still provides a plausible signal.
In some cases the engine may refuse to rev at all or stall shortly after startup.

Common causes, most likely first

A failed accelerator pedal position sensor 2 track inside the pedal assembly, which is the most common cause on high-mileage BMWs.
A short to voltage on the sensor 2 signal wire where the harness rubs against the pedal bracket or passes through the bulkhead.
Corroded or pushed-back pins in the pedal sensor connector, allowing the signal voltage to float high.
Water ingress into the pedal connector or footwell area, often from a blocked sunroof drain or windscreen cowl leak.
A faulty DME internal pull-up circuit on the sensor 2 input, though this is rare compared with pedal and wiring faults.
An intermittent short caused by a chafed harness near the steering column or pedal box after previous dashboard repairs.

How to diagnose and fix it

Read the live data for both pedal position sensors and compare their voltages through the full pedal sweep; sensor 2 should track sensor 1 inversely and stay within its specified range.
Visually inspect the accelerator pedal connector and the harness routing for corrosion, chafing, or pushed pins, and repair any damaged terminals before condemning parts.
Back-probe the sensor 2 signal wire at the DME connector and check for a short to battery voltage with the pedal at rest and while wiggling the harness.
Check the sensor 2 ground and reference voltage circuits for integrity, since a lifted ground can also drive the signal high.
If wiring and connectors pass inspection, replace the accelerator pedal assembly with a quality unit and clear the fault memory.
After repair, perform a throttle adaptation reset with a BMW-capable scan tool and verify both sensor voltages track correctly during a road test.

Why pedal sensor 2 fails before sensor 1

Sensor 2 is the lower-track potentiometer in the pedal assembly and wears faster because it sits closer to the pivot point, so it often fails first even though sensor 1 gets all the attention.
A high input code does not always mean the sensor is dead; a short to voltage from a chafed harness near the brake pedal switch or steering column can set the same code.
Water leaks into the driver footwell from a blocked sunroof drain or degraded windscreen cowl seal are a common hidden cause of pedal sensor corrosion on BMWs.
Clearing the code without performing a throttle adaptation can leave the DME running on default values, so the light may return even after a correct repair.
On some BMW models the pedal sensor signal passes through a connector behind the glovebox, and a loose connector there can mimic a failed pedal assembly.

Can I keep driving with P1223?

You can drive cautiously to a workshop if the car still accelerates smoothly, but avoid heavy throttle and motorway merging because limp mode can cut power without warning. If the engine will not rev or stalls repeatedly, stop driving and arrange recovery.

Tools that help

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Guidance is general and written for BMW vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.