OBD Guide

P0408

EGR Sensor B Circuit High

P0408 is an OBD-II diagnostic trouble code meaning: EGR Sensor B Circuit High. Common causes: egr sensor malfunction, open or shorted wiring harness. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • Unstable engine idling
  • Increased fuel consumption
  • Reduced engine power
  • Check Engine Light Illuminates

Causes

  • EGR sensor malfunction
  • Open or shorted wiring harness
  • Damage to sensor connectors
  • Malfunction of the engine control unit (ECU)

How to Fix

  1. Check the integrity of the EGR sensor wiring harness and connectors
  2. Test the EGR sensor for correct operation
  3. Replace EGR sensor if necessary
  4. Check and, if necessary, reflash the ECU

Related codes

Error P0408 by Vehicle Brand

FAQ

What does the P0408 code mean?

P0408 is an OBD-II diagnostic trouble code that indicates: EGR Sensor B Circuit High

What causes a P0408 error code?

The most common causes of P0408 include: EGR sensor malfunction; Open or shorted wiring harness; Damage to sensor connectors; Malfunction of the engine control unit (ECU).

How do I fix a P0408 diagnostic trouble code?

To fix P0408: Check the integrity of the EGR sensor wiring harness and connectors. Test the EGR sensor for correct operation. Replace EGR sensor if necessary. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P0408?

Limited driving only, diagnose soon

How much does it cost to fix P0408?

The estimated repair cost for P0408 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat