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P0651 Error Code Sensor Reference Voltage "A" Circuit Open

Updated: Oct 16

P0651 Error Code: Sensor Reference Voltage "A" Circuit Open

What it means : This error code is generated when the vehicle's engine control module (ECM) or power control module (PCM) detects an open in the sensor reference voltage circuit.


P0651 error code Potential Causes

1. Interruption in Sensor Reference Voltage Circuit: This error code may be generated if there is an interruption somewhere in the cables in the sensor reference voltage circuit.

2. Sensor Reference Voltage Circuit Connection Problem: There may be a problem with the connection points of the sensor reference voltage circuit.

3. Sensor Reference Voltage Sensor Failure: This circuit usually contains a sensor reference voltage sensor, and this sensor may be faulty.

4. Power Supply Problem: There may be a problem with the power supply to the sensor reference voltage circuit.



Symptoms:

· Check Engine Light is on

Decrease in engine performance

Obvious problems while the vehicle is running


How to Detect Error Code:

An OBD-II scanner can be used to identify the error code. This scanner can read the error codes from the vehicle's computer and determine what the problem is.




Correcting the Error Code:

1. Check Sensor Reference Voltage Circuit: Check the wiring connections in the sensor reference voltage circuit. Check for interruptions or open circuits.

2. Check Sensor Reference Voltage Sensor: If there is a sensor in this circuit, check that the sensor is operating properly. If necessary, replace a faulty sensor.

3. Check Electrical Connections: Check the connection points of the sensor reference voltage circuit.

4. Check the Power Source: Check the power source supplied to the circuit.


How Important Is The Error Code:

This error code indicates that there is a problem with the vehicle's sensor reference voltage circuit. This may affect the proper operation of the engine. It is generally recommended to resolve it immediately.


P0651

Things to Consider:

· Whether the control lamps are on or not

Changes in engine performance

Other symptoms and signs

Vehicle maintenance history

Conditions of use of the vehicle

When making evaluations about the error code, it would be more accurate to evaluate it specific to the specific make and model of the vehicle. Therefore, it is important to get more information by referring to your vehicle's user manual or the manufacturer.

The P0651 OBD-II (On-Board Diagnostics) error code refers to a "Sensor Reference Voltage 'A' Circuit Open" issue. This error code indicates a sensor reference voltage circuit issue detected by the vehicle's engine control module (ECM/PCM). Here is more information on this error code:




Sensor Reference Voltage "A" Circuit Open What is it?

This error indicates an open in the sensor reference voltage circuit (cable breakage, connection error, etc.). The sensor reference voltage is an electrical voltage required for the correct operation of various sensors.



How Does It Work?

1. Sensors: Many sensors in a vehicle require a specific reference voltage. This reference voltage is a basic reference point for the sensors to measure accurately.

2. Sensor Reference Voltage: The engine control module (ECM/PCM) provides a sensor reference voltage. This voltage is transmitted through the wires to the sensors.



What is it connected to?

Engine Control Module (ECM/PCM): The sensor reference voltage is usually controlled and provided by the engine control module.

Sensors: Many sensors require this reference voltage to operate properly.



What Kind of Malfunctions Occur?

1. Wiring Breaks or Connection Problems: Wiring breaks or connection problems in the sensor reference voltage circuit can prevent the sensors from operating properly.


What Does It Affect In Case Of Malfunction?

· Sensors Not Working Properly: When the sensor reference voltage is missing, this may cause the sensors not to measure correctly and therefore the engine control module not to make correct decisions.




How to Test?

1. Check for Error Codes: Check for error codes stored by the vehicle's engine control module. If error P0651 is detected, it indicates an open in the sensor reference voltage circuit.

2. Check Electrical Connections: Check the wiring in the sensor reference voltage circuit. Check for open or closed connections, connection problems, or shorts.

3. Using a Multimeter: Measure the sensor reference voltage using a multimeter. Check if the voltage has the correct values.

4. Check the Sensors: Check the sensors themselves. If a sensor is not receiving a reference voltage, this may help identify the source of the problem.

Get Expert Help: If you do not have the knowledge or experience to diagnose these types of electrical problems, it is important to get help from an automotive professional. Electrical work can be complex and may require expertise for proper diagnosis and repair.

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