Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that a part of the car's computer system that helps sensors work properly isn't getting the right power. Imagine if a toy didn't have enough battery power to work right.
The P0651 code indicates that the power supply to a group of sensors (referred to as 'Reference Voltage B') is not functioning properly, either due to an open circuit or a fault.
The P0651 code is triggered when the Powertrain Control Module (PCM) detects an abnormal voltage level in the sensor reference voltage circuit B. This circuit supplies a 5-volt reference signal to various sensors, and an open or short in this circuit can cause sensors to malfunction.
• Check Engine Light illuminated
• Poor engine performance
• Erratic transmission behavior
• Faulty sensor
• Open or shorted wiring in the reference voltage circuit
• Faulty PCM
PCM: Powertrain Control Module
OBD-II: On-Board Diagnostics, Second Generation
• Use an OBD-II scanner to confirm the code.
• Inspect wiring and connectors for damage or corrosion.
• Test the voltage at the sensor connector.
• Repair or replace damaged wiring or connectors.
• Replace the faulty sensor.
• Replace or reprogram the PCM if necessary.
• OBD-II scanner
• Multimeter
• Wiring repair tools
$100 - $500
Moderate
• Chevrolet Silverado
• GMC Sierra
• Ford F-150
• Regularly inspect wiring for wear and tear.
• Ensure sensors are properly connected.
• Perform routine maintenance checks.
Sensor Issue
• Avoid driving the vehicle until the issue is diagnosed.
• Consult a professional mechanic for accurate diagnosis.
Check with your vehicle manufacturer for warranty coverage on electronic components.
This code has been associated with wiring issues in vehicles with high mileage or those exposed to harsh environments.
Moderate – Addressing this issue promptly can prevent further sensor-related problems.
Driving with a malfunctioning sensor system can lead to increased emissions and reduced vehicle performance.
• Engine running
• Sensors connected
The sensors and wiring involved are typically located in the engine compartment.
Q: Can I drive with a P0651 code?
A: It's not recommended as it can lead to poor performance and potential damage.
Q: What sensors use the reference voltage B?
A: Various sensors like the throttle position sensor and manifold absolute pressure sensor may use this reference voltage.
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