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

Our certified mechanics come to you · Get a fair and transparent estimate upfront

EXCELLENT RATING ON

Cost of diagnosing the P0051 code

P0051 is a diagnostic trouble code (DTC) for "HO2S Heater Control Circuit Low (Bank 2 Sensor 1)". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic for $154.99 . Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $50.0 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate* Credit towards follow-up repair Earliest Availability
Ford $154.99 $50.0
Toyota $154.99 $50.0
BMW $164.99 $50.0

*Estimates may vary by market

SCHEDULE P0051 DIAGNOSTIC Get a fair and transparent estimate upfront

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.

Check Engine Light
P0051
trouble codes

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P0051 code.

SCHEDULE P0051 DIAGNOSTIC
Get a $50 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating

(8600)

Rating Summary
8017
273
65
46
199
8017
273
65
46
199
 at YourMechanic

Brandon

9 years of experience
133 reviews
Brandon
9 years of experience
Ford Escort L4-2.0L - Check Engine Light is on - Nashville, Tennessee
Brandon showed up ahead of schedule, was very personable and diagnosed my problems. He also scheduled my next appointments which will be with him.
 at YourMechanic

William

23 years of experience
33 reviews
William
23 years of experience
Lexus IS250 V6-2.5L - Check Engine Light is on - Mableton, Georgia
Arrived early which was great. William was courteous, and attentive to the issue. Even though it took several attempts I'm so happy he was determined to fix it and he did!
 at YourMechanic

Dan

40 years of experience
1080 reviews
Dan
40 years of experience
Plymouth Grand Voyager - Check Engine Light is on - Lawrenceville, Georgia
Mr. Dan Barber was quite patient, courteous and quite knowledgeable. From my observation, Mr. Barber appears to be quite professional.
 at YourMechanic

Christopher

9 years of experience
120 reviews
Christopher
9 years of experience
Ford Fiesta L4-1.6L - Check Engine Light is on - Smyrna, Georgia
Chris communicated with us each step of the way up until his arrival. He listened well, was knowledgeable, and was prepared. He took the time to diagnose the problem, explained the what, why and how and provided a solution. I would definitely recommend him and will use him again.


Related questions

Code P0051 shows up on my 03 Nissan Frontier SE crew cab. I have replaced all plug wires, plugs, rotor, cap, cabin filter, air fi
Oxygen sensors do not work until they reach a certain temperature. The electric heating element helps the sensor come up to temperature faster so that the engine can go into closed loop operation more quickly. P0051 says that there is...

More related articles

P0143 OBD-II Trouble Code: O2 Sensor Circuit Low voltage (Bank 1, Sensor 3)
Diagnostic Diagnostic Trouble Code (DTC): P0143 P0143 code definition O2 Sensor Circuit Low voltage (Bank 1 Sensor 3) What the P0143 code means P0143 is the OBD-II generic code indicating that the Engine Control Module (ECM) input from the O2...
P0423 OBD-II Trouble Code: Heated Catalyst Efficiency Below Threshold (Bank l)
P0423 P0423 code definition Heated Catalyst Efficiency Below Threshold (Bank l) What the P0423 code means P0423 is an OBD-II generic code that the engine control module (ECM) got input from the heated catalyst efficiency sensor for bank 1 that...
P2510 OBD-II Trouble Code: ECM/PCM Power Relay Sense Circuit Range/Performance
P2510 P2510 trouble code definition ECM/PCM Power Relay Sense Circuit Range/Performance What the P2510 code means P2510 is an OBD-II generic code for the engine control module detecting the ignition relay is open or shorted causing the relay to not...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com