Faulty accelerator pedal module or internal pedal sensor track fault; Damaged wiring, chafed or broken wires between the pedal sensor and the engine control unit; Corroded, loose or contaminated connector at the pedal module or control unit; Sensor supply voltage or ground fault affecting the pedal sensor; Low battery voltage or poor earth connections causing implausible signals; Fault inside the engine control unit.

P1542

Pedal Position Sensor Electrical.

BMW
Powertrain
Manufacturer code
High severity

How this code is built

P: SystemPowertrain
1: Defined byThe manufacturer
5: AreaVehicle speed, idle control and auxiliary inputs
42: FaultThe specific fault in that area

What it means

On BMW, P1542 means the engine control unit has found an electrical fault in the accelerator pedal position sensor circuit. The control unit compares the pedal sensor signals with each other and with expected voltage limits, and sets the code when a signal is out of range, missing, implausible or the supply is faulty. The car will usually go into a reduced-power or limp-home mode to protect against unintended acceleration.

Symptoms

Engine warning light on
Reduced power or limp-home mode
Slow, delayed or no throttle response
Engine stuck at a fixed or raised idle speed
Engine only revs to a limited speed
Possible stalling or hesitation when pulling away

Possible causes

Faulty accelerator pedal module or internal pedal sensor track faultlikely
Damaged wiring, chafed or broken wires between the pedal sensor and the engine control unitlikely
Corroded, loose or contaminated connector at the pedal module or control unitlikely
Sensor supply voltage or ground fault affecting the pedal sensorpossible
Low battery voltage or poor earth connections causing implausible signalspossible
Fault inside the engine control unitrare

How to diagnose

Read all stored fault codes and freeze frame data, and note whether other throttle, pedal or supply voltage codes are present.
Check battery condition and charging voltage, as low voltage can upset sensor readings.
Visually inspect the pedal module connector and wiring for damage, moisture, corrosion and bent or pushed-back pins.
Using live data, watch both pedal sensor signals while slowly pressing and releasing the pedal and check they move smoothly and agree with each other.
Check the sensor supply voltage and ground at the pedal connector against the manufacturer's specification for your model.
Wiggle-test the harness and connectors with live data running to find intermittent faults.
Test the wiring for continuity, short to earth and short to supply between the pedal connector and the control unit.
If wiring and supply are good, substitute or replace the pedal module, then clear codes and road test.

How to fix

Replace the accelerator pedal module if its signals are erratic, out of range or disagree.
Repair or replace damaged wiring sections and secure the harness away from chafing points.
Clean, repair or replace corroded or damaged connectors and terminals.
Restore correct supply and earth connections, including repairing poor earth points.
Replace or recharge a weak battery and fix any charging fault.
Have the control unit tested and, only if confirmed faulty, replaced and coded correctly for the vehicle.

Can I keep driving?

High severity

Avoid driving beyond what is needed, as limp-home mode and unpredictable throttle response can be unsafe in traffic. Have it checked promptly rather than continuing normal use.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.