Setting the P0051 Code
Low HO2S heating control circuit (Bank 2 sensor 1).
What does the P0051 code mean?
This code is set when the vehicle’s computer, the engine control module (ECM), detects a low system voltage in the heater control circuit. Specifically, the code refers to sensor 1 on bank 2. The code refers to sensor 1 on bank 2. The glow plug circuit in the heated oxygen sensor is designed to heat the sensor before the vehicle reaches operating temperature, so that the reading is accurate. This code can be seen with P0052.
What causes the P0051 code?
- Sensor 1 failure on bank 2
- Poor connection or disconnected connector
- Open or shorted circuit in wiring
- Burned heater circuit fuse
- ECM failure
What are the symptoms of the P0051 code?
With a P0051 code, the car will continue to run and drive; in most cases, the illuminated Check Engine light on the instrument panel will be the only noticeable symptom. Low fuel economy may be noticeable, and the vehicle may run unevenly.
How can a mechanic diagnose the P0051 code?
- Use a professional scan tool to check all current codes (must be used to display real-time sensor data).
- Observe and note all stop frame data that is associated with the code (to be used during the test drive).
- After confirming the P0051 code, clear the code and perform a test drive under the same conditions as shown in the freeze frame data.
- If the P0051 code reappears, perform a visual inspection to check the integrity of the wiring and sensor.
- If the previous step is OK, perform a scan with the live data monitoring tool of sensor 1 on bank 2.
- Check and test the ECM if the sensor is OK.
Frequent errors when diagnosing P0051 code.
Although the sensor itself is usually the cause of P0051, you need to use the right tools and perform the entire diagnostic procedure without skipping any steps to avoid unnecessary repairs. Monitoring the sensor data with the scan tool’s live data stream is the only way to verify proper operation, and the sensor should not be replaced until it has been tested.
How serious is the P0051 code?
The P0051 code has symptoms that are easy to treat, but like any other code, it should be corrected as soon as possible. In rare cases, when the vehicle breaks down and fuel consumption decreases, it is advisable to drive carefully to avoid problems.
What repairs can fix the P0051 code?
- Bank sensor replacement 2 1
- Resolve connection problems and reinstall connectors.
- Repair any open or shorted wires.
- Replace heating circuit fuse
- ECM Replacement
- P0051 can usually be repaired quickly at a reasonable cost by any qualified mechanic.
Additional notes on the P0051 code
If there is a blown fuse in the heater control circuit, there is always a reason for this; it is usually a short in the wiring. The fuse should be replaced after the wiring has been repaired.
A professional scan tool is needed to accurately and quickly diagnose P0051. A professional scan tool allows us to view sensor data in real time, such as voltage and resistance. In addition, it shows us changes in sensor readings as they occur.
