◆OBD Codes

P0325

Knock Sensor 1 Circuit Malfunction (Bank 1 or Single Sensor)

Moderatesensor

Overview

The P0325 diagnostic trouble code means the PCM has identified a knock sensor 1 circuit malfunction (bank 1 or single sensor) 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

  • Incorrect gauge readings
  • Check Engine Light (MIL) illuminated
  • Intermittent stalling
  • Reduced engine performance

Common Causes

  • Poor ground connection for sensor
  • Sensor contamination or buildup
  • Incorrect sensor installed
  • 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

Toyota CorollaMazda 3Honda CivicHyundai Elantra

Related Codes

P0115P0120P0335

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.