OBD Guide

P11BF

O2 Reference Voltage Circuit Low Voltage (NOx Sensor 2)

P11BF is an OBD-II diagnostic trouble code meaning: O2 Reference Voltage Circuit Low Voltage (NOx Sensor 2). Common causes: open or short circuit in the nox 2 sensor circuit, nox 2 sensor malfunction. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • Increased fuel consumption
  • Reduced engine power
  • Check Engine Light Is On
  • Increased level of harmful emissions

Causes

  • Open or short circuit in the NOx 2 sensor circuit
  • NOx 2 sensor malfunction
  • Problems with the engine control unit
  • Corroded contacts or damaged wiring harness

How to Fix

  1. Check NOx 2 sensor circuit continuity
  2. Check the resistance and voltage at the sensor
  3. Replace NOx 2 sensor if necessary
  4. Check and, if necessary, replace the engine control unit

Related codes

FAQ

What does the P11BF code mean?

P11BF is an OBD-II diagnostic trouble code that indicates: O2 Reference Voltage Circuit Low Voltage (NOx Sensor 2)

What causes a P11BF error code?

The most common causes of P11BF include: Open or short circuit in the NOx 2 sensor circuit; NOx 2 sensor malfunction; Problems with the engine control unit; Corroded contacts or damaged wiring harness.

How do I fix a P11BF diagnostic trouble code?

To fix P11BF: Check NOx 2 sensor circuit continuity. Check the resistance and voltage at the sensor. Replace NOx 2 sensor if necessary. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P11BF?

Yes, but get it checked soon

How much does it cost to fix P11BF?

The estimated repair cost for P11BF is $56–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat