Short to earth in the wiring of the sensor supply circuit (chafed or damaged loom); A faulty sensor on the shared supply pulling the voltage down internally; Water ingress, corrosion or damaged pins in a sensor or module connector; Low battery or system supply voltage, or poor module earth or power connections; Aftermarket accessory or poorly repaired wiring loading the circuit; Internal fault in the control module's reference voltage regulator.

P06B1

Sensor Power Supply A Circuit Low.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
6: AreaComputer and output circuits
B1: FaultThe specific fault in that area

What it means

P06B1 is a generic code meaning the control module has detected the voltage on Sensor Power Supply A (the regulated reference supply, usually 5 volts, feeding a group of sensors) is lower than expected. The module monitors this output and sets the code when the voltage falls below its calibrated limit. Which sensors share the supply depends on the make, model and engine.

Symptoms

Malfunction indicator lamp on
Poor or erratic engine running, or reduced power (limp mode)
Hard starting or no start
Several unrelated sensor codes stored at the same time
Warning lamps for other systems, depending on which sensors share the supply
Poor throttle or accelerator response

Possible causes

Short to earth in the wiring of the sensor supply circuit (chafed or damaged loom)likely
A faulty sensor on the shared supply pulling the voltage down internallylikely
Water ingress, corrosion or damaged pins in a sensor or module connectorpossible
Low battery or system supply voltage, or poor module earth or power connectionspossible
Aftermarket accessory or poorly repaired wiring loading the circuitpossible
Internal fault in the control module's reference voltage regulatorrare

How to diagnose

Read all stored codes and freeze frame data; note other sensor circuit codes that point to a shared supply
Check battery condition and charging voltage, as low system voltage can affect reference supplies
Inspect the wiring and connectors of the affected sensors for chafing, corrosion, water and pin damage
Use the manufacturer wiring diagram to identify which sensors share Sensor Power Supply A on this model and engine
With the ignition on, measure the reference voltage at the sensor connector and compare it with the specification
Unplug the sensors on the shared supply one at a time and watch whether the voltage returns to normal
Check the supply wire for short to earth and for resistance between sensors, with the module disconnected
Check module power and earth connections before suspecting the module

How to fix

Repair or replace the damaged wiring section causing the short to earth
Replace the sensor that is pulling the supply voltage down
Clean, repair or replace corroded or damaged connectors and terminals
Restore good battery condition or repair poor power and earth connections
Remove or correct faulty aftermarket wiring or accessories
Repair or replace the control module only after all wiring and sensors are proven good

Can I keep driving?

Medium severity

The car may be driveable, but it could go into limp mode or run poorly as sensor readings become unreliable. Get it checked soon, and avoid driving if it hesitates, stalls or loses power unpredictably.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.