OBD Guide

P1478

Particulate Matter Sensor Temperature Circuit High Voltage

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$33–89 (est.)

Symptoms

  • Check Engine Light Is On
  • Reduced engine power
  • Increased fuel consumption
  • Problems with diesel particulate filter regeneration
  • Unstable engine idling

Causes

  • Short circuit in the sensor circuit
  • Particle temperature sensor malfunction
  • Wiring harness damage
  • Problems with the engine control unit
  • Contact corrosion

How to Fix

  1. Check the integrity of the sensor wiring harness
  2. Measure resistance and voltage at the sensor
  3. Replace particle temperature sensor if necessary
  4. Clean or replace damaged wires
  5. Reset the error code and check the system

Related codes

Error P1478 by Vehicle Brand