P0123 Code – Throttle Position Sensor High Input

The P0123 code indicates that the Engine Control Unit (ECU) has detected a high voltage signal from the Throttle Position Sensor (TPS). A high input signal means the ECU interprets the throttle as wide open, even when the accelerator is not pressed. TPS operation: low throttle → low voltage high throttle → higher voltage In this case, the ECU receives too much voltage, usually due to an open circuit or signal short to voltage. Symptoms of Code P0123 Common symptoms include: Check Engine Light ON Sudden or unintended acceleration behavior High idle speed Engine hesitation Limp mode activation Poor throttle control In some cases, throttle response may become unpredictable. Common Causes of P0123 Typical causes include: Faulty TPS sensor Open circuit in signal wire Short to voltage Damaged wiring Corroded connectors Throttle body malfunction ECU issue (rare) How Serious Is Code P0123 The P0123 code is considered serious. It can cause: unsafe throttle behavior unexpected acceleration reduced control over the vehicle Immediate diagnosis is strongly recommended. How to Diagnose Code P0123 Diagnosis steps: Scan vehicle with OBD2 scanner Check TPS live data (may show high voltage at idle) Inspect wiring for open circuit or short Check connector condition Measure TPS voltage output Verify throttle movement vs signal How to Fix Code P0123 Possible solutions include: replace faulty TPS sensor repair wiring issues fix short to voltage clean or replace connectors inspect throttle body recalibrate throttle system clear code after repair Vehicles Commonly Affected The P0123 trouble code may appear on: Volkswagen BMW Opel Ford Toyota Audi Mercedes-Benz FAQ – P0123 Code Can I drive with code P0123? It is not recommended due to possible unsafe acceleration behavior. What does high input mean? It means high voltage signal, often caused by an open circuit. Can this trigger limp mode? Yes, frequently. Conclusion The P0123 code indicates a high voltage signal from the throttle position sensor, typically caused by wiring faults or sensor failure. Immediate repair is important for safe driving.