OBD Guide

P125B

Nitrogen Oxide Sensor Heating Heat Output Too Low During Operation

P125B is an OBD-II diagnostic trouble code meaning: Nitrogen Oxide Sensor Heating Heat Output Too Low During Operation. Common causes: nox sensor malfunction, problems in the sensor heating circuit. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • Check Engine Light Is On
  • Reduced engine power
  • Increased fuel consumption
  • Problems with passing technical inspection
  • Incorrect operation of the exhaust gas purification system

Causes

  • NOx sensor malfunction
  • Problems in the sensor heating circuit
  • Open or short circuit in wiring
  • Engine control unit malfunction
  • Poor contact in sensor connectors

How to Fix

  1. Check the integrity of the sensor heating circuit
  2. Inspect connectors and wiring for damage
  3. Check the resistance of the sensor heating element
  4. If necessary, replace the NOx sensor
  5. Check and update engine control unit software

Related codes

FAQ

What does the P125B code mean?

P125B is an OBD-II diagnostic trouble code that indicates: Nitrogen Oxide Sensor Heating Heat Output Too Low During Operation

What causes a P125B error code?

The most common causes of P125B include: NOx sensor malfunction; Problems in the sensor heating circuit; Open or short circuit in wiring; Engine control unit malfunction.

How do I fix a P125B diagnostic trouble code?

To fix P125B: Check the integrity of the sensor heating circuit. Inspect connectors and wiring for damage. Check the resistance of the sensor heating element. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P125B?

Yes, but get it checked soon

How much does it cost to fix P125B?

The estimated repair cost for P125B is $56–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat