OBD Guide

P11FC

O2 Low Reference Circuit (NOx Sensor 2)

P11FC is an OBD-II diagnostic trouble code meaning: O2 Low Reference Circuit (NOx Sensor 2). Common causes: nox sensor number 2 malfunction, open or short circuit in sensor wiring. 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
  • Increased fuel consumption
  • Reduced engine power
  • Engine transition to emergency mode
  • Increased emissions of harmful substances

Causes

  • NOx sensor number 2 malfunction
  • Open or short circuit in sensor wiring
  • Sensor power problems
  • Corrosion of contacts or connectors
  • Malfunction of the engine control unit (rare)

How to Fix

  1. Check NOx sensor number 2 wiring and connectors for damage.
  2. Check the power supply and ground of the sensor
  3. Check NOx sensor resistance and signal
  4. Replace NOx sensor number 2 if necessary
  5. Reset the error code and check the system

Related codes

FAQ

What does the P11FC code mean?

P11FC is an OBD-II diagnostic trouble code that indicates: O2 Low Reference Circuit (NOx Sensor 2)

What causes a P11FC error code?

The most common causes of P11FC include: NOx sensor number 2 malfunction; Open or short circuit in sensor wiring; Sensor power problems; Corrosion of contacts or connectors.

How do I fix a P11FC diagnostic trouble code?

To fix P11FC: Check NOx sensor number 2 wiring and connectors for damage.. Check the power supply and ground of the sensor. Check NOx sensor resistance and signal. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P11FC?

Yes, but get it checked soon

How much does it cost to fix P11FC?

The estimated repair cost for P11FC is $56–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat