OBD Guide
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P11D1

O2 Signal Circuit Low Voltage (NOx Sensor 2)

P11D1 is an OBD-II diagnostic trouble code meaning: O2 Signal Circuit Low Voltage (NOx Sensor 2). Common causes: nox 2 sensor malfunction, open or short circuit in the sensor circuit. Estimated repair cost: $50–278.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$50–278 (est.)

Symptoms

  • Check Engine light comes on
  • Reduced engine power
  • Increased fuel consumption
  • Unpleasant exhaust smell
  • The engine may go into emergency mode

Causes

  • NOx 2 sensor malfunction
  • Open or short circuit in the sensor circuit
  • Poor contact in sensor connectors
  • Problems with wiring or harness
  • Engine control unit (ECU) malfunction

How to Fix

  1. Check the integrity of the wiring and connectors of the NOx sensor 2
  2. Check the voltage and resistance in the sensor circuit
  3. Clean sensor connector contacts
  4. If necessary, replace NOx 2 sensor
  5. Diagnose the engine control unit

Related codes

P11D0P11D2P11D3

FAQ

What does the P11D1 code mean?

P11D1 is an OBD-II diagnostic trouble code that indicates: O2 Signal Circuit Low Voltage (NOx Sensor 2)

What causes a P11D1 error code?

The most common causes of P11D1 include: NOx 2 sensor malfunction; Open or short circuit in the sensor circuit; Poor contact in sensor connectors; Problems with wiring or harness.

How do I fix a P11D1 diagnostic trouble code?

To fix P11D1: Check the integrity of the wiring and connectors of the NOx sensor 2. Check the voltage and resistance in the sensor circuit. Clean sensor connector contacts. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P11D1?

Yes, but get it checked soon

How much does it cost to fix P11D1?

The estimated repair cost for P11D1 is $50–278. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat