◆OBD Codes

P0123

Throttle/Pedal Position Sensor/Switch "A" Circuit High

Severesensor

Overview

The P0123 diagnostic trouble code means the PCM has identified a throttle/pedal position sensor/switch "a" circuit high problem. This code indicates that a sensor or its circuit is not providing expected readings to the engine management system. Faulty sensor data can cause the PCM to make incorrect adjustments, affecting engine performance.

Symptoms

  • Hard starting in certain conditions
  • Poor fuel economy
  • Intermittent stalling
  • Incorrect gauge readings

Common Causes

  • Corroded or damaged sensor connector
  • Faulty PCM (Powertrain Control Module)
  • Sensor contamination or buildup
  • Faulty sensor (out of range or failed)

Diagnosis Steps

  1. 1Connect an OBD-II scanner and read all stored trouble codes and freeze frame data
  2. 2Locate the specific sensor referenced by the code
  3. 3Inspect the sensor connector for corrosion, damage, or loose pins
  4. 4Test the sensor output using a multimeter or scan tool live data
  5. 5Check the wiring between the sensor and the PCM for opens or shorts

Estimated Repair Cost

$75 — $350

Cost varies by vehicle, location, and repair shop. Includes parts and labor.

Commonly Affected Vehicles

Mazda 3Kia ForteSubaru ImprezaChevrolet Cruze

Related Codes

P0325P0335P0110

More Sensor Codes

P0070Ambient Air Temperature Sensor Circuit
Low
P0071Ambient Air Temperature Sensor Range/Performance
Low
P0072Ambient Air Temperature Sensor Circuit Low
Low
P0073Ambient Air Temperature Sensor Circuit High
Low
P0074Ambient Air Temperature Sensor Circuit Intermittent
Low
P0095Intake Air Temperature Sensor 2 Circuit
Low

Frequently Asked Questions

Most automotive sensors last 80,000-150,000 miles, though this varies by sensor type and driving conditions. Oxygen sensors and temperature sensors tend to degrade gradually over time.