OBD Guide

P23B9

NOx Sensor Heater Sense Circuit High Bank 1 Sensor 3

P23B9 is an OBD-II diagnostic trouble code meaning: NOx Sensor Heater Sense Circuit High Bank 1 Sensor 3. Common causes: nox sensor heater circuit open, poor contact in the sensor connector. Estimated repair cost: $167–444.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$167–444 (est.)

Symptoms

  • Check Engine Light Is On
  • Increased fuel consumption
  • Reduced engine power
  • Increased NOx emissions
  • Unstable engine operation at idle

Causes

  • NOx sensor heater circuit open
  • Poor contact in the sensor connector
  • Malfunction of the NOx sensor itself
  • Wiring harness damage
  • Problems with the engine control unit

How to Fix

  1. Check the continuity of the NOx sensor heater circuit
  2. Inspect connectors and contacts for corrosion or damage
  3. Check sensor heater resistance
  4. If necessary, replace the NOx sensor
  5. Reset the error code and check if it returns

Related codes

Error P23B9 by Vehicle Brand

FAQ

What does the P23B9 code mean?

P23B9 is an OBD-II diagnostic trouble code that indicates: NOx Sensor Heater Sense Circuit High Bank 1 Sensor 3

What causes a P23B9 error code?

The most common causes of P23B9 include: NOx sensor heater circuit open; Poor contact in the sensor connector; Malfunction of the NOx sensor itself; Wiring harness damage.

How do I fix a P23B9 diagnostic trouble code?

To fix P23B9: Check the continuity of the NOx sensor heater circuit. Inspect connectors and contacts for corrosion or damage. Check sensor heater resistance. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P23B9?

Yes, but get it checked soon

How much does it cost to fix P23B9?

The estimated repair cost for P23B9 is $167–444. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat