P0651 OBD-II Trouble Code: Sensor Reference Voltage B Circuit Open

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

Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0651 code

P0651 is a diagnostic trouble code (DTC) for "Sensor Reference Voltage B Circuit Open". 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. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 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$20.00
Toyota$20.00
BMW$20.00
SCHEDULE P0651 DIAGNOSTIC Get a fair and transparent estimate upfront

P0651 code definition

The P0651 indicates that the sensor reference voltage B circuit is open. This code applies to all manufacturers.

What the P0651 code means

This generic code shows that there is some type of fault in the sensor reference voltage "B", and is detected by one of the other sensor 5 voltage circuits or the engine control module or ECM. The voltage could be higher or lower than expected.

What causes the P0651 code?

A number of different things could potentially cause the P0651 code. The common causes include:

What are the symptoms of the P0651 code?

The symptoms of a P0651 code can vary, so it is important to get an understanding of the different issues you might face. It might include a hard or no start condition, the engine could start running rough, or you might notice that the vehicle no longer has the same fuel efficiency that it once did. The engine might misfire, and you would likely notice a lack of power in the vehicle. If the trouble code is stored, and the Check Engine Light isn’t on, it might show the code as pending. However, in other cases, the engine light might be on.

How does a mechanic diagnose the P0651 code?

The Onboard Diagnostics II standardized system is a computer system in many cars and trucks today that allows the vehicle to run self-diagnostics and reports. A mechanic will utilize an OBD-II scanner to diagnose the problem with your vehicle and access data regarding the fault and necessary repair. They will examine the data to determine when a code was set, reset the codes, and then test the vehicle to determine when the code returns, if it does. In many cases, the mechanic will be able to determine the problem based on the data they receive. Determining that it is the P0651 code and not one of the other trouble codes lets them know the next actions they need to take to help get the vehicle back in shape.

Common mistakes when diagnosing the P0651 code

The biggest mistakes when dealing with the P0651 code diagnosis, or any diagnosis for that matter, is spending time looking at symptoms and stored codes that are present in the vehicle that might not have anything to do with the P0651 code. If a mechanic tries to rush through the job or skips parts of the testing process, they will not get an accurate result, and they will often misdiagnose the vehicle’s actual problems. Naturally, this will lead to repairs that do not work.

How serious is the P0651 code?

The P0651 sensor code can be a big problem for your vehicle. While it might still be possible to drive the vehicle, at least for a time, the fuel efficiency may suffer. As mentioned earlier, in some cases the vehicle will be more difficult to start, and it might not start up at all. It’s always a good idea to get any issues with your vehicle fixed as quickly as possible.

What repairs can fix the P0651 code?

The following are some of the common ways to deal with the P0651 code:

Additional comments for consideration regarding the P0651 code

Many vehicles will start to have sensor issues as they get older and have more miles put onto them, and it doesn’t always mean it is a sign to worry. Have the mechanic check with the OBD-II scanner, test the vehicle, and reset the codes. Many times, the codes will not return, and you will not need to do any repairs to the vehicle. However, if the code does come back and the issues with your vehicle continue or get worse, you will want to take it in for repair.

Need help with a P0651 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.

P0651
trouble codes
Check Engine Light

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P0651 code.

SCHEDULE P0651 DIAGNOSTIC
Get a $20 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating

(6,114)

Rating Summary
5,655
221
51
35
152
5,655
221
51
35
152

Kevin

24 years of experience
388 reviews
Kevin
24 years of experience
Chevrolet Tracker - Check Engine Light is on - Stone Mountain, Georgia
Kevin was pretty cool! He explained things to me in a way I could understand and was able to offer me some good options to fix my car problems! Very professional and knew his stuff! Excellent experience

JOHNNY

33 years of experience
63 reviews
JOHNNY
33 years of experience
Toyota Camry - Check Engine Light is on - Carmichael, California
Johnny was early, friendly, and thorough! He explained things to me about my car that I had no idea about before! I booked him for a diagnostic appointment and I’m definitely requesting him for a follow-up!

Benji

22 years of experience
184 reviews
Benji
22 years of experience
Jaguar XK - Check Engine Light is on - Phoenix, Arizona
Will absolutely recommend Benjie to all my friends, thorough and knowledgeable. Will have him back fit all future car repairs!

Marco

29 years of experience
124 reviews
Marco
29 years of experience
Kia Soul - Check Engine Light is on - Riverside, California
Marco was great. Cam on time, and explained everything he did. Also gave good recommendation for fixing as the problem has a Kia recall.


More related articles

P0632 OBD-II Trouble Code: Odometer Not Programmed – ECM/PCM
P0632 means that the PCM is unable to read the odometer due to battery in the vehicle becoming discharged or for electrical reasons.
5 Warning Lights You Should Never Ignore
Car warning lights tell you something in your car needs attention. If you see the Check Engine Light or other warnings, get it inspected right away.
P0775 OBD-II Trouble Code: Pressure Control Solenoid B Malfunction
P0775 means there is insufficient fluid pressure within a solenoid operating the automatic transmission due to leaks, low or dirty fluid.

Related questions

The Check Engine Light comes back on after I reset it

When the Check Engine Light comes on without any specific warning, this can indicate a variety of possible issues. Unfortunately, without more specific symptoms, this can be tough to diagnose without the use of a scanning tool and the skill...

My Check Engine Light came on. I fixed the issue, but the light quickly came back on. Will it turn itself off?

Just because a code is displayed does not mean that part is bad in all cases. The code is used as a tool to diagnose the problem. You may have to have the code diagnosed by an experienced mechanic like...

Shifting issues, check engine light on

Hello there, a few different things could potentially cause this fault. The most common would be a neutral safety switch, transmission shift linkage fault, or a transmission fault. A technician will first inspect the Check Engine Light for exactly what...

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