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P0651 Chevrolet Code - 5 Volt Reference 2 Circuit

Quick Answer

The P0651 Chevrolet diagnostic trouble code indicates a problem with the 5 volt reference 2 circuit in the vehicle's engine control module (ECM). Common causes include Faulty wiring or connectors in the 5 volt reference circuit, Malfunctioning sensor or component connected to the circuit, Short circuit or open circuit in the wiring. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P0651 Chevrolet indicates 5 Volt Reference 2 Circuit.
Common causes
Common causes include Faulty wiring or connectors in the 5 volt reference circuit, Malfunctioning sensor or component connected to the circuit, Short circuit or open circuit in the wiring.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
What is this?
Table of contents Created and updated by William Orellana on Aug 19, 2024
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Code P0651 Chevrolet Description

The P0651 Chevrolet diagnostic trouble code indicates a problem with the 5 volt reference 2 circuit in the vehicle's engine control module (ECM). The 5 volt reference circuit is responsible for providing a stable 5-volt power supply to various sensors and components in the engine and transmission systems. When this circuit malfunctions, it can lead to inaccurate sensor readings, which can affect the vehicle's performance and drivability.

OBDII Code P0651 Chevrolet - 5 Volt Reference 2 Circuit
P0651 Chevrolet Code - 5 Volt Reference 2 Circuit

Common Causes of P0651 Chevrolet

  1. Faulty wiring or connectors in the 5 volt reference circuit
  2. Malfunctioning sensor or component connected to the circuit
  3. Short circuit or open circuit in the wiring
  4. ECM (Engine Control Module) failure
  5. Corrosion or damage to the circuit connections

Symptoms of P0651 Chevrolet

  1. Check engine light illuminated on the dashboard
  2. Poor engine performance
  3. Rough idling or stalling
  4. Engine misfires
  5. Difficulties starting the vehicle

How to Fix P0651 Chevrolet

  1. Use a diagnostic scanner to read and record the fault codes, including P0651.
  2. Inspect the wiring, connectors, and components associated with the 5 volt reference 2 circuit for any visible damage or corrosion.
  3. Test the sensors and modules connected to the circuit to identify any faulty components.
  4. Repair or replace any damaged wiring, connectors, sensors, or modules as necessary.
  5. Clear the fault codes from the ECM memory and perform a test drive to ensure the issue has been resolved.

Cost to Fix P0651 Chevrolet

The typical repair costs for addressing the P0651 Chevrolet code can vary depending on the specific cause of the issue and the extent of the repairs needed. In general, the cost of parts and labor for this repair can range from $100 to $500. It's important to consider the diagnostic time and labor rates at auto repair shops, which can impact the overall cost of the repair. It's recommended to consult with a professional mechanic for a more accurate cost estimate based on your vehicle's make and model.

What does this mean?

Tech Notes for P0651 Chevrolet

Disconnecting one component at a time from the affected 5 Volt reference circuit while observing the scan tool 5 Volt Reference Circuit Status parameter may help locate the fault. The scan tool parameter will change from Malfunction to OK when the source of the fault is disconnected. If all 5 Volt reference components have been disconnected and a fault is still indicated, the fault may exist in the wiring harness.

The 5 Volt reference 2 circuit provides 5 Volt to the following sensors: (Some models may have different sensors, please consult the factory service manual for the list of sensors for your model and year)

- Brake pedal position sensor
- Crankshaft position sensor





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Information for Specific Chevrolet Models

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0651 Chevrolet Code

1. What does the OBDII code P0651 Chevrolet mean?

The code P0651 Chevrolet indicates a problem with the 5 Volt Reference 2 Circuit in the vehicle.

2. What are the common symptoms of a P0651 Chevrolet code?

Common symptoms include engine stalling, rough idling, poor acceleration, and in some cases, the vehicle may not start at all.

3. What are the possible causes of the P0651 Chevrolet trouble code?

Possible causes include a faulty 5-volt reference circuit, damaged wiring or connectors, a defective ECM, or issues with the sensor connected to the 5-volt reference circuit.

4. How can I diagnose the P0651 Chevrolet code?

Diagnosing the code involves checking the wiring and connectors related to the 5-volt reference circuit, testing the sensors connected to the circuit, and using a multimeter to measure voltage levels.

5. Can I continue driving with a P0651 Chevrolet trouble code?

It is not recommended to drive with a P0651 code as it can lead to further damage to the vehicle and potentially unsafe driving conditions.

6. How do I repair a P0651 Chevrolet trouble code?

Repairing the P0651 code involves identifying the root cause of the issue, repairing or replacing damaged wiring or connectors, and addressing any faulty sensors or components.

7. Is it safe to reset the trouble code without fixing the underlying issue?

Resetting the trouble code without fixing the underlying problem is not recommended, as the issue will likely reoccur and could potentially cause more severe problems over time.

8. Can a DIY enthusiast fix the P0651 Chevrolet trouble code?

While some DIY enthusiasts may be able to diagnose and repair the issue causing the P0651 code, it is recommended to seek professional help for proper diagnosis and repair.

9. How much does it cost to repair a P0651 Chevrolet trouble code?

The cost of repairing a P0651 code can vary depending on the root cause of the issue, the extent of the damage, and whether any components need to be replaced. It is advisable to consult a mechanic for an accurate estimate.

10. How can I prevent the P0651 Chevrolet trouble code from occurring again?

Regular maintenance, such as checking the wiring and connectors, ensuring proper sensor function, and addressing any electrical issues promptly, can help prevent the recurrence of the P0651 trouble code.

Discuss the causes and fixes for P0651 Chevrolet OBDII Code

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  • I recently bought a 2004 silverado 2500hd 6.0, my engine light came on and it gave me the knock sensor code. I drove the truck for seven days with no problem. I reset the light to get rid of the light for a few miles or so, after doing this the truck idled for about five minutes then I put it in drive and it started to idle rough and I lost power. I tried to restart and it wouldn't until after the third try. It started up and I drove but as I was driving it shook and turned off on me I put it in neutral and it turned back on. I lost gas power intermittently then all of a sudden it kicked out and drove smooth. I drove it a few hours later and the engine lite turned off and no symptoms were felt. About a block from the mechanic the light came back on. It gave the knock sensor code and the crankshaft position sensor code. That day I had the crankshaft sensor replaced thinking it would fix the problem, it didn't a few. Miles after picking it up it didn't want to start up again. I let it set while arranging a tow truck and I went to try to start it after 15 minutes or so and it fired up with a rough idle. The mechanic took it back and tried to get the truck to duplicate the symptoms but had no luck. I drove it on Saturday a few miles and I let it idle while I went into the auto parts to get the knock sensors and when I came back the truck was off with the key on, I tried to start it once and it had a rough idle once again, I turned it off then on again and it ran fine. Today I replaced the knock sensors and it runs nice. I cleared the light and after driving about five miles or so the light came back on only this time it gave me code po651, ac pressure and fuel pressure, the truck and ac are running awesome. Any idea what's going on..

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