OBD Guide

U05A9

NOx Sensor C Received Invalid Data From ECM/PCM

U05A9 is an OBD-II diagnostic trouble code meaning: NOx Sensor C Received Invalid Data From ECM/PCM. Common causes: nox c sensor malfunction, damage to the wiring to the nox sensor. 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 comes on
  • Reduced engine power
  • Increased fuel consumption
  • Problems with passing technical inspection
  • Possible transition to emergency mode

Causes

  • NOx C sensor malfunction
  • Damage to the wiring to the NOx sensor
  • Poor contact in connectors
  • Software error in the ECU
  • Sensor power problems

How to Fix

  1. Check the condition of the wiring and connectors of the NOx C sensor
  2. Read error codes and sensor data using a scanner
  3. Check the power supply and ground of the sensor
  4. Replace NOx C sensor if necessary
  5. Update the ECU firmware if appropriate service bulletins are available

Related codes

Error U05A9 by Vehicle Brand

FAQ

What does the U05A9 code mean?

U05A9 is an OBD-II diagnostic trouble code that indicates: NOx Sensor C Received Invalid Data From ECM/PCM

What causes a U05A9 error code?

The most common causes of U05A9 include: NOx C sensor malfunction; Damage to the wiring to the NOx sensor; Poor contact in connectors; Software error in the ECU.

How do I fix a U05A9 diagnostic trouble code?

To fix U05A9: Check the condition of the wiring and connectors of the NOx C sensor. Read error codes and sensor data using a scanner. Check the power supply and ground of the sensor. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U05A9?

Yes, but get it checked soon

How much does it cost to fix U05A9?

The estimated repair cost for U05A9 is $167–444. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat