P0051 OBD Error Code: Problem & Solutions

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Is your Car’s Check Engine Light illuminating on the dashboard? Do you find sudden decrease in the fuel economy? And is the car engine running rough with black smoke coming from tailpipe? This might be the indication of problems with the oxygen sensor of the car which in other words can be an OBD P0051 error.

The OBD P0051 error is set when the car’s Engine Control Module (ECM) detects low system voltage in the heater control circuit, especially in the Engine Bank 2 and Sensor 1.

P0051 Error Code basically refers to the problem with the Oxygen Sensor 1 located in the Bank 2 side of the engine near the catalytic converter. The O2 sensor is referred to as the air/fuel ratio sensor which detects the amount of oxygen in the exhaust gas compared to the outside air and then vehicle's computer adjusts the air/fuel ratio going into the engine. The sensor becomes less effective when the exhaust gas temperature is low, so it includes a heater which is activated to help get better readings from the A/F O2 sensor. Essentially this P0051 code means that the resistance of the heater circuit is lower than normal. In most cases, that resistance level must fall below 0.8 A to trigger the DTC code.

What causes this problem with the HO2S Heater Control Circuit Low?

• Failure of ECM/PCM
• Problematic Fuse leading to a Blown Heater Circuit
• Faulty Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1
• Harness of Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1 is Open Shorted
• Poor Electrical Connection in the Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1
• Faulty Catalytic Converter

1. Heated Oxygen Sensor - The faulty oxygen sensor affects fuel/air mixture, engine timing and engine combustion intervals. A faulty sensor is a major reason behind the OBD Error Code P0051 flashing on the ECM and immediate replacement is required.
2. Heated Oxygen Sensor Harness - If the sensor harness is damaged, the first indication will be flashing of Check Engine light on the dashboard. It is advised the replace with the new one. Buy quality auto parts from us.
3. Heated Oxygen Sensor Connector - A Faulty Oxygen Sensor Connector directly affects the engine performance. Thus, replace your old/damaged connectors immediately.
4. Heater Circuit Fuse - Damaged Heater Circuit Fuse will in turn affect the efficiency of the engine and requires immediate replacement. Visit us for quality fuses and parts.
5. Engine Control Module - OBD Error Code P0051 can also be due to faulty ECMs. This may lead to engine stalling or not starting, and check engine lights being on. It’s better to get the faulty electricals replaced as soon as possible.
6. Powertrain Control Module - P0051 error code also relates to problems with the powertrain control module. Find all the Powertrain related parts with us.
7. Catalytic Converter - Catalytic converters can overheat because of excessive amounts of unburned gas caused by a misfiring spark plug or a leaky exhaust valve. In addition, a faulty oxygen sensor can cause overheating. Replace your old catalytic converter now!
8. Diagnostic Tool - Use correct diagnostic tools to detect and correct the OBD error properly and correctly.
9. Auto Switches & Sensors - Common causes behind that P0051 error code can be defective switches or faulty sensors. So it will be a good decision to replace them now.

It is really important to understand the symptoms of this problem before you go any diagnosis. With the OBD Error Code P0051, there can be many symptoms that can affect the performance of the vehicle. Visit Parts Avatar Canada today to find genuine replacement and performance auto parts for your vehicle. Some of the common symptoms are as follows;

Common Symptoms

• Check Engine light is on
• Affects the engine performance when driving
• May cause leakage in exhaust valve
• Might lead to stalling and not starting of the engine
• Loss of engine power
• Inefficient fuel consumption

Some of the common fixes for the problems in the OBD Code P0051 for all makes and models are as follows;

• Replace the air/fuel oxygen sensor 1 on Bank 2
• Fixing the issues in the circuit connection
• Reattachment of connectors properly
• Repairing open or shorted wiring
• Repair the fuse of the heater circuit
• PCM (or ECM) replacement
• Replacing the catalytic converter 

We have stocked a wide range of best priced oxygen sensors, ECM/PCM parts and a lot more to help you out in fixing your car.

It is important to conduct a proper diagnosis before doing any repairs of the vehicle. With that, you will need to conduct a proper inspection of the connectors and the wiring that leads to the oxygen sensor. If the engine system has a heater relay and fuse, you will have to check those as well. For a more thorough diagnosis, you will need to use a digital volt ohm meter, especially to:

• Use a professional grade Diagnostic scan tool to check for all codes present (must be used to show live sensor data).
• Observe and take note of any freeze frame data that is associated with the code (to be used in test drive).
• After P0051 is confirmed, clear the code and perform a test drive under the same circumstances shown in the freeze frame data.
• If the P0051 code returns, perform a visual inspection to check the integrity of the wiring and sensor.
• Scan with a tool used to monitor live data from Bank 2 Sensor 1 if the previous step is found to be okay.
• Check and test the ECM if the sensor checks out.

Common Mistakes When Diagnosing OBD Code P0051

Though the sensor itself is generally the cause of P0051, using the proper tools and following the complete diagnostic procedure without skipping any steps is required as to avoid unneeded repairs. Monitoring the sensor data from the scan tool live data stream is the only way to check for proper operation, and the sensor should not be replaced until it is tested.

P0051 has easily managed symptoms but like any other code, it should be repaired at the earliest convenience. In rare cases where the vehicle runs poorly and the fuel economy goes down, caution is advised when driving to avoid any issues.