P2256

O2 Sensor Negative Current Control Circuit High Bank 2 Sensor 1

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

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
If necessary, replace the oxygen sensor
Check and reflash the ECU if necessary

Related codes

P2257 P2255 P2237