Short to a higher voltage (such as battery voltage) in the wiring of the sensor reference supply, caused by chafed or damaged insulation; Faulty sensor on the shared supply circuit that is internally shorted to a higher voltage; Damaged, corroded or water-contaminated connector terminals causing a cross-connection between circuits; Poor ground or reference return connection making the measured supply voltage read high; Previous wiring repair or aftermarket accessory wiring that has crossed circuits; Fault inside the engine control module's internal sensor supply regulator; Outdated or faulty control module software, where the manufacturer has documented it as a cause for the specific model.

P06B5

Sensor Power Supply B Circuit High.

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
B5: FaultThe specific fault in that area

What it means

P06B5 means the engine control module has detected a voltage that is too high on sensor power supply circuit B, which is a regulated reference voltage (commonly 5 volts) shared by a group of sensors. Which sensors share this supply depends on the make, model and engine. The module sets the code when it measures the reference voltage above its expected range for longer than the allowed time.

Symptoms

Engine warning light on
Reduced power or limp mode
Poor or erratic throttle response
Rough running or hesitation
Other sensor fault codes stored at the same time
Hard starting or cutting out in some cases

Possible causes

Short to a higher voltage (such as battery voltage) in the wiring of the sensor reference supply, caused by chafed or damaged insulationlikely
Faulty sensor on the shared supply circuit that is internally shorted to a higher voltagelikely
Damaged, corroded or water-contaminated connector terminals causing a cross-connection between circuitspossible
Poor ground or reference return connection making the measured supply voltage read highpossible
Previous wiring repair or aftermarket accessory wiring that has crossed circuitspossible
Fault inside the engine control module's internal sensor supply regulatorrare
Outdated or faulty control module software, where the manufacturer has documented it as a cause for the specific modelrare

How to diagnose

Read all stored and pending codes and the freeze frame data, noting any other sensor circuit codes that share the same supply
Check the manufacturer's wiring diagram to identify which sensors are on supply circuit B for this model and engine
Visually inspect the related wiring and connectors for chafing, heat damage, water ingress, bent or pushed-back pins and signs of previous repairs
Check the battery and charging system voltage, as abnormal supply voltage can upset other readings
With the ignition on, measure the voltage at the sensor supply pin and compare it with the specified value
Unplug the sensors on the shared supply one at a time and see whether the voltage returns to normal, which points to the faulty sensor
With the module and sensors disconnected, test the supply wire for a short to voltage and check ground and return circuit resistance
If wiring and sensors are proven good, check for applicable software updates and consider module fault only after all other tests

How to fix

Repair or replace damaged wiring and ensure the harness is properly secured and routed away from sharp edges and heat
Replace the sensor that is shorting the supply to a higher voltage
Clean or repair corroded connectors and terminals, or replace the connector, and seal against moisture
Repair poor ground or return connections
Reverse any faulty aftermarket wiring modifications
Update the control module software if a documented update addresses this fault, or repair or replace the module if it is proven faulty

Can I keep driving?

Medium severity

The car may be driven carefully for a short distance if it runs normally, but get it checked soon as the affected sensors may give false readings and the engine may go into limp mode. Stop driving if power is severely reduced or the engine runs very poorly.

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