OBD Guide

P2256

O2 Sensor Negative Current Control Circuit High Bank 2 Sensor 1

P2256 is an OBD-II diagnostic trouble code meaning: O2 Sensor Negative Current Control Circuit High Bank 2 Sensor 1. Common causes: open or short circuit in the oxygen sensor circuit, bank 2 sensor 1 oxygen sensor malfunction. Estimated repair cost: $28–89.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$28–89 (est.)

Symptoms

  • Check Engine light comes on
  • Increased fuel consumption
  • Unstable engine idling
  • Reduced engine power
  • Dips during acceleration

Causes

  • Open or short circuit in the oxygen sensor circuit
  • Bank 2 Sensor 1 Oxygen Sensor Malfunction
  • Connector problems or contact corrosion
  • Engine ECU malfunction
  • Wiring harness damage

How to Fix

  1. Check the integrity of the sensor wiring and connectors
  2. Measure the resistance and voltage in the sensor circuit
  3. Check the operation of the Bank 2 Sensor 1 oxygen sensor
  4. If necessary, replace the oxygen sensor
  5. Check and reflash the ECU if necessary

Related codes

Error P2256 by Vehicle Brand

FAQ

What does the P2256 code mean?

P2256 is an OBD-II diagnostic trouble code that indicates: O2 Sensor Negative Current Control Circuit High Bank 2 Sensor 1

What causes a P2256 error code?

The most common causes of P2256 include: Open or short circuit in the oxygen sensor circuit; Bank 2 Sensor 1 Oxygen Sensor Malfunction; Connector problems or contact corrosion; Engine ECU malfunction.

How do I fix a P2256 diagnostic trouble code?

To fix P2256: Check the integrity of the sensor wiring and connectors. Measure the resistance and voltage in the sensor circuit. Check the operation of the Bank 2 Sensor 1 oxygen sensor. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P2256?

Yes, but get it checked soon

How much does it cost to fix P2256?

The estimated repair cost for P2256 is $28–89. Actual cost depends on your vehicle, location, and labor rates.

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