Exception in rendering!

Message: window is not defined

ReferenceError: window is not defined
    at new c (/tmp/execjs20161208-83728-162u1bgjs:136:3912)
    at m.mountComponent (/tmp/execjs20161208-83728-162u1bgjs:47:15602)
    at /tmp/execjs20161208-83728-162u1bgjs:49:31860
    at a.r.perform (/tmp/execjs20161208-83728-162u1bgjs:47:12503)
    at Object.a [as renderToString] (/tmp/execjs20161208-83728-162u1bgjs:49:31821)
    at r (/tmp/execjs20161208-83728-162u1bgjs:50:21164)
    at Object.S.ReactOnRails.serverRenderReactComponent (/tmp/execjs20161208-83728-162u1bgjs:32:6073)
    at eval (eval at <anonymous> (/tmp/execjs20161208-83728-162u1bgjs:173:8), <anonymous>:10:23)
    at eval (eval at <anonymous> (/tmp/execjs20161208-83728-162u1bgjs:173:8), <anonymous>:17:3)
    at /tmp/execjs20161208-83728-162u1bgjs:173:8

P0051 OBD-II Trouble Code: HO2S Heater Control Circuit Low (Bank 2 Sensor 1)

check engine light

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 circumstances 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.

Additional comments for consideration regarding the P0051 code

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?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

Post a question and get free advice from our certified mechanics.

ASK A QUESTION

More related articles

P0121 OBD-II Trouble Code: TPS "A" Circuit Range Performance Problem
P0121 code definition Throttle Pedal Position Sensor/Switch (TPS) A Circuit Range Performance Problem What the P0121 code means P0121 is a generic OBD-II code which indicates that the Engine Control...
P0222 OBD-II Trouble Code: Throttle/Pedal Position Switch/Sensor B Circuit Low Input
P0222 code definition Throttle/Pedal Position Switch/Sensor B Circuit Low Input What the P0222 code means The manufacturer specifies a range of acceptable voltage to be produced from the throttle position...
P2159 OBD-II Trouble Code: Vehicle Speed Sensor B Range/Performance
Diagnostic Trouble Code (DTC): P2159 P2159 code definition Vehicle Speed Sensor B Range/Performance Related Trouble Codes: P2158: Vehicle Speed Sensor B P2160: Vehicle Speed Sensor B Circuit Low P2161:...


Related questions

Q: Dodge Neon SE 2003 problem is code P0440

The trouble code P0440 means the Evaporative emission control system is malfunction. This malfunction may have been caused by a number of different things including, a loose or missing gas cap, a vacuum leak, a faulty purge valve, an issue...

Q: Possible issue with the shift solenoid or TCM?

It could be either one and it's impossible to say without inspecting the car. The difference between the O'Reilly diagnosis and the dealer's is probably one of equipment. O'Reilly uses a generic OBD-II scanner and the dealer should be using...

Q: Egr and evap codes 455 & 405

The trouble code P0405 is for the EGR sensor. This code indicates that the sensor is not giving correct voltage readings. You'll need to replace the sensor and the sensor hoses. The hoses can clog or burn through which causes...