P0051 code definition
HO2S Heater Control Circuit Low (Bank 2 Sensor 1)
What the P0051 code means
This code is set when the car’s computer, or Engine Control Module (ECM), detects low system voltage in the heater control circuit. Specifically, the code is referencing Bank 2 Sensor 1. The heater circuit in the heated oxygen sensor is for warming the sensor before the vehicle reaches operating temperature for an accurate reading. This code may be seen with P0052.
What causes the P0051 code?
- Bank 2 Sensor 1 failure
- Poor connection or disconnected connector
- Open or short in the wiring
- Blown heater circuit fuse
- ECM failure
What are the symptoms of the P0051 code?
With the P0051 code, a car will still run and drive; in most cases, the illuminated Check Engine Light on the dashboard will be the only noticeable symptom. Poor fuel economy may be noticed, and the vehicle may run roughly.
How does a mechanic diagnose the P0051 code?
Uses a professional grade scan tool to check for all codes present (must be used to show live sensor data)
Observes and takes note of any freeze frame data that is associated with the code (to be used in test drive)
After P0051 is confirmed, clears the code and performs a test drive under the same circ*mstances shown in the freeze frame data
If the P0051 code returns, performs a visual inspection to check the integrity of the wiring and sensor
Scans with a tool used to monitor live data from Bank 2 Sensor 1 if the previous step is found to be okay
Checks and tests the ECM if the sensor checks out
Common mistakes when diagnosing the P0051 code
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's live data stream is the only way to check for proper operation, and the sensor should not be replaced until it is tested.
How serious is the P0051 code?
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.
What repairs can fix the P0051 code?
P0051 is generally a quick fix with a reasonable cost at any qualified mechanic.
If a fuse is found to be blown in the heater control circuit, there is always a reason for it; generally a wiring short. The fuse must be replaced after wiring is repaired.
A professional level scan tool is required to precisely and quickly diagnose P0051. The professional scan tool allows us to view live data from the sensor, such as the voltage and resistance. In addition, this shows us changes in the sensor readings as they occur.
Need help with a P0051 code?
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Check Engine Light
P0051
trouble codes
FAQs
The P0051 code stands for “HO2S Heater Control Circuit Low (Bank 2 Sensor 1).” It's triggered when the PCM detects a potential issue with the heater circuit for the oxygen sensor #1 on Bank 2. Possible causes for this code to be set include a faulty O2 sensor, O2 sensor heater circuit issues, and a faulty PCM.
Where is the bank 2 sensor 1 on a P0050? ›
The diagnostic trouble code P0050 relates to the issues the Engine Control Module (ECM) finds with the heater control circuit of the primary oxygen sensor 1 on the bank 2 side of the engine. Bank 2 is located opposite the side of the engine that houses the number 1 cylinder.
Where is the oxygen sensor heater control circuit low bank 1 sensor 1? ›
The P0030 triggers when your vehicle's Engine Control Module (ECM) detects a fault in the heater circuit of the primary oxygen sensor on the bank 1 side of the engine. Cylinder number 1 sits on the bank 1 side of the engine, while sensor 1 is between the engine and the catalytic converter.
What is the code P0052 Bank 2 sensor 1? ›
The P0052 code stands for “HO2S Heater Circuit High Voltage (Bank 2, Sensor 1),” which typically means the powertrain control module (PCM) detected a mismatch between the desired and actual state of the control circuit of the heated oxygen sensor (HO2S) 1 on bank 2.
What is 02 sensor heater circuit bank 1 sensor 2? ›
Bank 1 Sensor 2 is the oxygen (O2) sensor that's in the middle of the catalytic converter or right behind the front catalytic converter (the converter that's closest to the engine). Bank 1 Sensor 1 is the sensor between the engine and the catalytic converter.
What is the symptoms of P0050 code? ›
What are the Common Symptoms of the P0050 Code?
- Check engine light is on.
- Decreased fuel efficiency.
- Decreased engine performance.
The Sensor 2 in question means that it is the sensor that is located behind your catalytic converter and the Bank 2 side of the engine is the side that does not contain the #1 cylinder.
How much does it cost to fix a heater control circuit? ›
Furnace control board replacement cost typically ranges from $50 to $900, though most homeowners spend an average of $500. The cost to replace a control board depends on local labor rates, inspection fees, and the potential need for other services, such as maintenance or additional repairs.
What are the symptoms of ho2s heater control circuit bank 1 sensor 2? ›
One of the most common symptoms of the P0036 code is that the ECM will illuminate your vehicle's Check Engine Light. You will also notice a decrease in the engine performance in your car, as well as increased fuel consumption. You may also find that the catalytic converter cannot perform as efficiently as usual.
Where is the heater control circuit bank 2 sensor 2? ›
The oxygen sensor 2 is located on bank 2, which is the side of the engine that doesn't contain the #1 cylinder. The bank 2 sensor 2 oxygen sensor is also referred to as the downstream oxygen sensor due to its location after the catalytic converter.
The “Bank 2” in this definition refers to the side of the engine that does not contain the number one cylinder. Meanwhile, the “Sensor A” refers to the intake camshaft sensor.
What are the symptoms of a bad O2 sensor heater circuit? ›
Other common symptoms include your engine running excessively rich. This is the result of an engine running in open loop. Your engine may also run rough due to the oxygen sensor issue. It's important to determine the cause quickly and find a workable solution.
Where is the O2 sensor heater located? ›
Oxygen sensors are typically located in the exhaust system. In most modern vehicles, you can find two sensors near the motor and two sensors near your catalytic converter.
What controls the O2 sensor heater circuit? ›
The O2 sensor's heater circuit is controlled in one of two ways. First is the positively controlled type of circuit. If the O2 sensor heater circuit's negative wire goes directly to ground, look for a short-to-power problem. Usually the heater circuit in this case is controlled by a relay.
What cylinder is Bank 2 sensor 1? ›
If you know which cylinder that is number 1, there makes no difference if you have an inline or transverse engine. Bank 1 is always on cylinder 1 – 3 – 5 – 7 – 9 – 11 and bank 2 is always on cylinder 2 – 4 – 6 – 8 – 10 – 12.
What is the code for the O2 sensor bank 2 sensor 1? ›
A P0150 code has to do with one of the oxygen sensors which are some of the most common reasons you will see a check engine light in your car. What the P0150 code specifically refers to is there is an oxygen sensor circuit malfunction on Sensor 1 on the Bank 2 side of the vehicle.
