OBD Guide

P30B4

NOx Sensor 1 Signal Message Counter Incorrect

P30B4 is an OBD-II diagnostic trouble code meaning: NOx Sensor 1 Signal Message Counter Incorrect. Common causes: nox sensor 1 malfunction, problems with wiring to the sensor. 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
  • Possible transition to emergency mode
  • Increased emissions of harmful substances

Causes

  • NOx sensor 1 malfunction
  • Problems with wiring to the sensor
  • Corrosion or poor contact in connectors
  • Engine control module malfunction
  • Sensor power problems

How to Fix

  1. Check the integrity of the wiring to the sensor
  2. Check connections and connector contacts
  3. Test the NOx sensor using diagnostic equipment
  4. If necessary, replace NOx sensor 1
  5. Reset the error code and check the system

Related codes

FAQ

What does the P30B4 code mean?

P30B4 is an OBD-II diagnostic trouble code that indicates: NOx Sensor 1 Signal Message Counter Incorrect

What causes a P30B4 error code?

The most common causes of P30B4 include: NOx sensor 1 malfunction; Problems with wiring to the sensor; Corrosion or poor contact in connectors; Engine control module malfunction.

How do I fix a P30B4 diagnostic trouble code?

To fix P30B4: Check the integrity of the wiring to the sensor. Check connections and connector contacts. Test the NOx sensor using diagnostic equipment. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P30B4?

Yes, but get it checked soon

How much does it cost to fix P30B4?

The estimated repair cost for P30B4 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat