AutoCodes – Mercedes-Benz – P0651 Mercedes-Benz

P0651 Mercedes-Benz Code - Sensor Reference Voltage 'B' Circuit/Open

Quick Answer

This fault code is stored in the Engine Control Module (ECM) when a malfunction occurs with the sensor supply voltage circuit. Common causes include Check other codes, Faulty Sensor, Sensor harness is open or shorted. 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 Mercedes-Benz indicates Sensor Reference Voltage 'B' Circuit/Open.
Common causes: Common causes include Check other codes, Faulty Sensor, Sensor harness is open or shorted.
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.

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Code Popularity 13,802

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Sep 09, 2019

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0651 Mercedes-Benz Description

This fault code is stored in the Engine Control Module (ECM) when a malfunction occurs with the sensor supply voltage circuit. The engine control module outputs a five volt supply voltage to certain sensors. Many components share the same five volt supply. If fault codes exist for multiple components which operate with a five volt supply the wiring from the ECM and the ECM itself should be tested. Also each component should be disconnected in turn to identify a faulty component pulling down the supply circuit.

OBDII Code P0651 Mercedes-Benz - Sensor Reference Voltage 'B' Circuit/Open - AutoCodes.com — P0651 Mercedes-Benz Code - Sensor Reference Voltage 'B' Circuit/Open

What does this mean?

What are the Possible Causes of the DTC P0651 Mercedes-Benz?

Check other codes
Faulty Sensor
Sensor harness is open or shorted
Sensor circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P0651 Mercedes-Benz?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

Mercedes Benz Code = 0093 Power supply (P0651)

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0651 Mercedes-Benz code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0651 Mercedes-Benz code?

Need more information on how to fix the P0651 Mercedes-Benz code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0651 Mercedes-Benz code diagnosed by a professional: Find a repair shop in your area

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 Mercedes-Benz Code

1. What are the common symptoms of OBDII code P0651 in a Mercedes-Benz?

The common symptoms of OBDII code P0651 in a Mercedes-Benz include issues with the engine performance, rough idling, stalling, and potential problems with the vehicle's sensor readings.

2. What does the OBDII code P0651 for a Mercedes-Benz indicate?

OBDII code P0651 for a Mercedes-Benz indicates a problem with the Sensor Reference Voltage 'B' Circuit/Open, which means that there is an issue with the reference voltage being supplied to a sensor in the vehicle.

3. What are the possible causes of OBDII code P0651 in a Mercedes-Benz?

Possible causes of OBDII code P0651 in a Mercedes-Benz include a faulty sensor, damaged wiring or connectors, a problem with the engine control module (ECM), or issues with the power supply to the sensor.

4. How can I diagnose the OBDII code P0651 in my Mercedes-Benz?

Diagnosing OBDII code P0651 in a Mercedes-Benz involves using an OBDII scanner to read the code, checking the sensor reference voltage, inspecting the wiring and connectors for damage, and testing the sensor and related components for proper functionality.

5. Is it safe to continue driving my Mercedes-Benz with OBDII code P0651?

It is not recommended to continue driving your Mercedes-Benz with OBDII code P0651, as it can lead to potential engine performance issues and further damage to the vehicle if left unresolved.

6. Can I repair OBDII code P0651 in my Mercedes-Benz myself?

Repairing OBDII code P0651 in a Mercedes-Benz may require advanced diagnostic skills and tools. It is advisable to consult with a professional mechanic or dealership for proper diagnosis and repair.

7. How much does it typically cost to repair OBDII code P0651 in a Mercedes-Benz?

The cost of repairing OBDII code P0651 in a Mercedes-Benz can vary depending on the underlying cause of the issue, the parts needed for repair, and the labor costs. It is recommended to obtain estimates from different service providers.

8. Can a faulty sensor cause OBDII code P0651 in a Mercedes-Benz?

Yes, a faulty sensor can cause OBDII code P0651 in a Mercedes-Benz if it is not receiving the correct reference voltage due to internal damage or malfunction.

9. Are there any preventive measures to avoid OBDII code P0651 in a Mercedes-Benz?

Regular maintenance, including checking and replacing sensors as needed, inspecting wiring for damage, and addressing any electrical issues promptly, can help prevent OBDII code P0651 in a Mercedes-Benz.

10. How long does it typically take to repair OBDII code P0651 in a Mercedes-Benz?

The time required to repair OBDII code P0651 in a Mercedes-Benz can vary depending on the extent of the issue and the availability of parts. It is best to consult with a professional mechanic for an accurate estimate of the repair timeline.