Faulty accelerator pedal position sensor (worn tracks or internal failure); Damaged or corroded wiring harness between the pedal sensor and the DME; Loose or contaminated electrical connector at the pedal sensor; Short to ground in the sensor signal circuit; Failed DME (engine control module) internal driver, though rare; Water intrusion or debris in the pedal assembly area

DTC codes / BMW codes / P1122

P1122 · BMWPedal Position Sensor 1 Low Input

Q: What does code P1122 mean?

Pedal Position Sensor 1 Low Input. P1122 on a BMW means the engine control module (DME) has detected an abnormally low voltage signal from the accelerator pedal position sensor 1 circuit. The DME expects a specific voltage range as you press the pedal, and a low input tells it the sensor is reporting a closed throttle or a short to ground when it should not be.

P1122 on a BMW means the engine control module (DME) has detected an abnormally low voltage signal from the accelerator pedal position sensor 1 circuit. The DME expects a specific voltage range as you press the pedal, and a low input tells it the sensor is reporting a closed throttle or a short to ground when it should not be.

SystemPowertrain

Code typeBMW specific

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering

Symptoms you may notice

Illuminated check engine light, often with no other noticeable symptoms
Reduced engine power or limp mode, limiting acceleration
Hesitation or stumble when pressing the accelerator
Unresponsive or delayed throttle response
Rough idle or stalling in some cases
Electronic throttle control warning message on the iDrive screen

Common causes, most likely first

Faulty accelerator pedal position sensor (worn tracks or internal failure)
Damaged or corroded wiring harness between the pedal sensor and the DME
Loose or contaminated electrical connector at the pedal sensor
Short to ground in the sensor signal circuit
Failed DME (engine control module) internal driver, though rare
Water intrusion or debris in the pedal assembly area

How to diagnose and fix it

Read fault memory with a BMW-capable scan tool and record freeze-frame data for P1122
Visually inspect the accelerator pedal sensor connector and wiring for corrosion, chafing, or loose pins
Measure sensor 1 signal voltage at the pedal connector with the key on and pedal at rest and fully pressed, comparing to BMW specifications
Check for continuity and short-to-ground on the signal wire between the pedal sensor and the DME
If wiring and connector are good, replace the accelerator pedal assembly with the integrated sensor
Clear fault memory and perform a throttle adaptation reset using the scan tool
Road test to confirm the code does not return and throttle response is normal

Why P1122 is often a wiring issue

A low input code frequently comes from a chafed signal wire near the pedal bracket rather than a failed sensor, so always inspect the harness before replacing parts.
The accelerator pedal sensor on many BMW models is not sold separately from the pedal assembly, making a wiring repair the more cost-effective first step.
P1122 can be set intermittently by a loose connector that only loses contact over bumps, so wiggle-test the harness while watching live sensor data.
A weak or failing battery can cause voltage drops that mimic sensor faults on BMWs, so verify charging system health before condemning the pedal sensor.
After any repair, a throttle adaptation reset is required; otherwise the DME may continue to set the code even with a good sensor.

Can I keep driving with P1122?

You can usually drive the car to a workshop, but expect reduced power and possible limp mode. Avoid heavy acceleration or highway merging until the fault is repaired, as throttle response may be unpredictable.

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.