DTC Code P1123 – What does this code mean for BMW?

<ul> <li><b>Engine Light ON (or Service Engine Soon Warning Light)</b>: The engine control module (ECM) detects an abnormally high voltage signal from the pedal position sensor 1. This could be due to a faulty pedal position sensor, wiring issues, or a malfunctioning ECM.</li> <li><b>Reduced Engine Performance</b>: The vehicle may enter a 'limp mode' to prevent damage, resulting in reduced power and acceleration. This is often caused by the ECM receiving incorrect data from the pedal position sensor.</li> <li><b>Unresponsive Throttle</b>: The throttle may not respond correctly to pedal input, leading to delayed or erratic acceleration. This can be due to a malfunctioning pedal position sensor or related wiring issues.</li> </ul>

<ul><li>The pedal position sensor may be faulty, leading to incorrect readings.</li><li>An open or shorted harness in the pedal position sensor can disrupt the signal.</li><li>Poor electrical connections in the pedal position sensor circuit can cause intermittent or incorrect signals.</li></ul>

<ul> <li><b>Initial Scan</b>: Use an OBD-II scanner to confirm the presence of DTC P1123 and check for any additional codes.</li> <li><b>Visual Inspection</b>: Inspect the accelerator pedal and its wiring for any visible damage, loose connections, or corrosion.</li> <li><b>Check Pedal Position Sensor (PPS)</b>: Test the Pedal Position Sensor 1 using a multimeter to ensure it is within the manufacturer's specified range.</li> <li><b>Inspect Connector and Wiring</b>: Examine the connector and wiring harness for the PPS for any signs of wear, damage, or disconnection.</li> <li><b>Test Voltage Supply</b>: Verify that the PPS is receiving the correct voltage supply from the ECU. Refer to the BMW service manual for the exact voltage specifications.</li> <li><b>Check Ground Connection</b>: Ensure that the ground connection for the PPS is secure and free of corrosion.</li> <li><b>ECU Diagnostics</b>: If all previous steps are satisfactory, perform a diagnostic check on the ECU to rule out any internal faults.</li> <li><b>Clear Codes and Test Drive</b>: Clear the DTC codes and perform a test drive to see if the code reappears. Monitor the pedal position sensor readings during the drive.</li></ul>

<p>The DTC code P1123 for BMW indicates a 'Pedal Position 1 High Input'. This is a critical issue as it affects the throttle control, potentially leading to unexpected acceleration or loss of throttle response.</p><ul><li><b>Immediate Actions:</b> Inspect the pedal position sensor and related wiring for faults or damage.</li><li><b>Potential Risks:</b> Delayed repair can result in unsafe driving conditions and potential accidents.</li></ul>