OBD Guide

P11FD

O2 Low Reference Circuit Low Voltage (NOx Sensor 2)

P11FD is an OBD-II diagnostic trouble code meaning: O2 Low Reference Circuit Low Voltage (NOx Sensor 2). Common causes: nox 2 sensor malfunction, open or short circuit in the sensor circuit. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • Check Engine Light Is On
  • Reduced engine power
  • Increased fuel consumption
  • Unstable engine idling
  • Dips during acceleration

Causes

  • NOx 2 sensor malfunction
  • Open or short circuit in the sensor circuit
  • Poor contact in the sensor connector
  • Sensor power problems
  • Engine ECU malfunction

How to Fix

  1. Check the integrity of the wiring to the NOx sensor 2
  2. Check connections and contacts in the sensor connector
  3. Measure resistance and voltage at the sensor
  4. Replace NOx 2 sensor if necessary
  5. Test the operation of the system after repair

Related codes

FAQ

What does the P11FD code mean?

P11FD is an OBD-II diagnostic trouble code that indicates: O2 Low Reference Circuit Low Voltage (NOx Sensor 2)

What causes a P11FD error code?

The most common causes of P11FD include: NOx 2 sensor malfunction; Open or short circuit in the sensor circuit; Poor contact in the sensor connector; Sensor power problems.

How do I fix a P11FD diagnostic trouble code?

To fix P11FD: Check the integrity of the wiring to the NOx sensor 2. Check connections and contacts in the sensor connector. Measure resistance and voltage at the sensor. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P11FD?

Limited driving only, diagnose soon

How much does it cost to fix P11FD?

The estimated repair cost for P11FD is $56–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat