OBD Guide

P0405

EGR Sensor A Circuit Low

P0405 is an OBD-II diagnostic trouble code meaning: EGR Sensor A Circuit Low. Common causes: open or short circuit in the sensor wiring harness, faulty egr valve position sensor. Estimated repair cost: $33–167.

Severity
⚠️ Medium
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$33–167 (est.)

Symptoms

  • Rough idle
  • Dips during acceleration
  • Increased fuel consumption
  • Power Loss
  • Check Engine Light Illuminates

Causes

  • Open or short circuit in the sensor wiring harness
  • Faulty EGR valve position sensor
  • Poor electrical contact or corrosion in connectors
  • EGR valve malfunction
  • Problems with power or grounding of the circuit

How to Fix

  1. Visual inspection of the wiring harness and connectors for damage
  2. Checking the voltage and resistance in the sensor circuit
  3. Testing the EGR position sensor
  4. Cleaning or replacing the EGR valve if necessary
  5. Reset error code and test drive

Related codes

Error P0405 by Vehicle Brand

FAQ

What does the P0405 code mean?

P0405 is an OBD-II diagnostic trouble code that indicates: EGR Sensor A Circuit Low

What causes a P0405 error code?

The most common causes of P0405 include: Open or short circuit in the sensor wiring harness; Faulty EGR valve position sensor; Poor electrical contact or corrosion in connectors; EGR valve malfunction.

How do I fix a P0405 diagnostic trouble code?

To fix P0405: Visual inspection of the wiring harness and connectors for damage. Checking the voltage and resistance in the sensor circuit. Testing the EGR position sensor. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P0405?

Do not drive — repair immediately

How much does it cost to fix P0405?

The estimated repair cost for P0405 is $33–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat