What is the P2251 fault number? What is the O2 Sensor Negative current Control Circuit / Open Bank1 Sensor 1 error code description? How can you fix P2251 fault codes? What are the symptoms and causes of the P2251 error code? …..
What is the P2251 fault code? What does it all mean?
P2251 is an OBD-II generic malfunction code that has been identified. “O2 Sensor Negative Current Control Circuit / Open Bank 1 Sensor 1” This code indicates that there is a problem in the heated oxygen sensor circuit (HO2S). This code is activated if the powertrain controller module (PCM), fails to receive an oxygen sensor signal (Sensor 1) from the first bank. “Bank 1” The code refers to V-type engines. “Sensor 1” The oxygen sensor nearest to the engine is before the catalyst.
Modern cars have at least two oxygen sensors per engine bank. One of these sensors is called the “Catalytic Converter” and precedes the catalytic convert. The “upstream oxygen detector” . The second is the one after the catalytic convert and is called the “downstream oxygen sensor” . These sensors are identical in appearance, but they have different functions. The upstream oxygen sensors are used to monitor the oxygen level in the exhaust and adjust the air-fuel mixture. The downstream oxygen sensor monitors the efficiency of catalytic converter.
The oxygen content in the exhaust stream will affect the voltage of the O2 sensor upstream. A vehicle running well is indicated by a lot of exhaust gas. “poor” . The engine will also run in low air. “rich” . This information is used by PCM to balance the air-fuel mixture. It adjusts the pulse widths for the fuel injectors to reduce or increase the fuel being sent to the combustion chamber.
Ground circuit is the negative current control circuit. The circuit is ground and if a fault occurs, the sensor will not work properly. In such cases, the P2251 fault code will be set and the engine fault lamp activated.
Some vehicles are at risk of the P2251 fault code, including but not limited to: Mini, Hyundai Acura, Mazda Mercedes Benz and Volvo models, as well as Toyota, Volkswagen, Honda Jaguar, Ford, Opel Lexus and Lexus.
What causes the P2251 fault code?
Here are some reasons why P2251 should be set.
- – Exhaust Leakage
- – Defective oxygen sensor (Bank 1 Sensor 1)
- – Connectors and wires that are not connected to the oxygen sensor heater circuit have been damaged, snapped or melted.
- – Ground wire causing weak electricity
- – Use aftermarket parts
- – A PCM is not working properly or has to be reprogrammed
What are the symptoms for P2251 Fault Code
These symptoms may be present if you own a vehicle that has the code P2251.
- – Illumination for the check engine light
- – Engine hard start
- – Sudden acceleration causes loss of power
- – Increased fuel use
- – Misfires and rich/poor codes
- – As the PCM loses control of fuel, the PCM enters failsafe mode
How to Fix the P2251 Fault Code
There are several repairs that can resolve the P2251 fault code.
- – Repair or replacement O2 sensor wiring harness, connectors or open or short circuit issues
- – Repairing exhaust leaks which caused the O2 sensor’s failure
- – Fixing O2 sensor heater circuit issues
- – Inspecting the ground and power cables connecting the sensor and the PCM.
- – Replacing the faulty oxygen sensor
- – Reprogramming and replacing the PCM
How Serious Is the P2251 Fault Code
P2251 is a serious malfunction code. A fault in the O2 sensor heater circuit may cause the PCM to lose control of fuel management. The PCM could enter failsafe mode. Poor engine performance can lead to various issues in driveability. The catalytic convertor could be damaged if the code is not corrected promptly. It is important to address it immediately and fix it as soon as possible.
