Open circuit in the power supply wire between the PCM and the sensors, often due to a broken wire or corroded connector; Short to ground on the sensor power supply circuit, which may be caused by a chafed wire touching metal; Faulty sensor internally shorted, pulling the supply voltage down; Corroded or damaged connector terminals at the PCM or at any sensor on the shared supply; Failed PCM power supply output driver (less common); Aftermarket accessories or poor previous repairs tapping into the sensor reference circuit

DTC codes / P06xx · Computer and output circuits / P06B0

P06B0Sensor Power Supply A Circuit/Open

Q: What does code P06B0 mean?

Sensor Power Supply A Circuit/Open. P06B0 indicates that the powertrain control module has detected an open circuit or low voltage on the power supply feed (often labeled Sensor Power Supply A) that feeds a group of sensors, typically 5-volt reference sensors. The computer monitors the voltage on this supply line and sets the code when it falls outside the expected range, usually because the circuit is open or shorted to ground.

P06B0 indicates that the powertrain control module has detected an open circuit or low voltage on the power supply feed (often labeled Sensor Power Supply A) that feeds a group of sensors, typically 5-volt reference sensors. The computer monitors the voltage on this supply line and sets the code when it falls outside the expected range, usually because the circuit is open or shorted to ground.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaComputer and output circuits

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Multiple sensor-related codes stored in the computer, such as those for the mass airflow sensor, throttle position sensor, or manifold absolute pressure sensor
Rough running or stalling if the affected sensors include those critical for engine operation
Reduced engine power or limp mode in some vehicles
Poor fuel economy or increased emissions due to incorrect sensor readings
Intermittent driveability issues if the open circuit is temperature or vibration sensitive

Common causes, most likely first

Open circuit in the power supply wire between the PCM and the sensors, often due to a broken wire or corroded connector
Short to ground on the sensor power supply circuit, which may be caused by a chafed wire touching metal
Faulty sensor internally shorted, pulling the supply voltage down
Corroded or damaged connector terminals at the PCM or at any sensor on the shared supply
Failed PCM power supply output driver (less common)
Aftermarket accessories or poor previous repairs tapping into the sensor reference circuit

How to diagnose and fix it

Use a scan tool to record all stored codes and freeze-frame data, then clear codes and verify if P06B0 returns immediately
With the key on and engine off, measure voltage at the sensor power supply wire at each sensor connector on the circuit; a good supply should read close to 5 volts (or 12 volts depending on the sensor) and any reading significantly lower indicates a problem
Disconnect sensors one by one while monitoring the supply voltage to see if a faulty sensor is loading down the circuit
Perform a continuity and resistance test on the power supply wire from the PCM to each sensor, checking for opens, shorts to ground, and excessive resistance
Inspect all connectors and harnesses along the circuit for corrosion, loose pins, or chafed wires, and repair as needed
If the circuit and sensors check out, test the PCM output with a known-good load or substitute a known-good PCM to confirm a failed driver
After repairs, clear codes and perform a road test to ensure the code does not return and all sensor readings are normal

What the 5-Volt Reference Really Tells You

A single shorted sensor on the shared 5-volt reference line can pull down the voltage for all sensors on that circuit, causing multiple unrelated sensor codes and misleading you into replacing good parts.
The code description 'Sensor Power Supply A' often refers to the 5-volt reference circuit, but on some vehicles it may be a 12-volt supply for specific sensors; always consult the wiring diagram for the exact vehicle.
Intermittent open circuits caused by vibration or temperature changes may not show up during a static test; wiggle-test the harness while monitoring the supply voltage with a meter or scan tool.
Aftermarket alarms, remote starters, or poorly installed accessories that tap into the sensor reference wire are a common cause of this code that many technicians overlook.
A failed PCM is rarely the root cause; confirm all wiring and sensors are good before condemning the computer, as misdiagnosis often leads to unnecessary PCM replacement.

Can I keep driving with P06B0?

If the check engine light is on but the engine runs normally, you can drive the vehicle short distances to a repair shop, but avoid heavy acceleration or towing. If the engine runs rough, stalls, or enters limp mode, stop driving and have the vehicle towed to prevent damage or unsafe operation.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.