Open circuit, chafed or broken wire in the reference voltage supply wiring; Corroded, loose or pushed-out pins in a sensor or control unit connector on the shared supply; A sensor on the shared supply with an internal open circuit or fault; Poor earth or supply to the control unit affecting the reference output; Previous repair damage or rodent damage to the harness; Fault inside the control unit's reference voltage output.

P06D2

Sensor Reference Voltage E Circuit/Open.

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
D2: FaultThe specific fault in that area

What it means

P06D2 is a generic code meaning the control unit has detected an open circuit on the sensor reference voltage 'E' supply. This is the regulated supply (usually 5 volts) that powers a group of sensors, and the control unit saw the voltage or current on it fall outside the expected range, consistent with a break in the circuit. Which sensors share reference 'E' depends on the make, model and engine, so the wiring diagram is needed to identify them.

Symptoms

Engine warning light on
Engine running in limp mode or with reduced power
Poor or erratic throttle response
Rough running, hesitation or stalling
Other sensor fault codes stored at the same time
Hard starting or no start in some cases

Possible causes

Open circuit, chafed or broken wire in the reference voltage supply wiringlikely
Corroded, loose or pushed-out pins in a sensor or control unit connector on the shared supplylikely
A sensor on the shared supply with an internal open circuit or faultpossible
Poor earth or supply to the control unit affecting the reference outputpossible
Previous repair damage or rodent damage to the harnesspossible
Fault inside the control unit's reference voltage outputrare

How to diagnose

Read all stored codes and freeze frame data, noting which other sensor codes are set, as they point to the sensors sharing reference E
Check for related manufacturer information and the wiring diagram to identify which sensors and connectors use reference E for this model and engine
Visually inspect the harness and connectors on those sensors for chafing, damage, corrosion, moisture or loose pins
Check the control unit's earth and power supply connections for good condition and voltage
With the ignition on, measure the reference voltage at the sensor connectors and compare it with the specified value
Unplug the sensors on the circuit one at a time and see whether the voltage returns to normal, which points to a faulty sensor
With the battery disconnected and the control unit unplugged, test the wiring for continuity from the control unit to each sensor, and for shorts to earth or supply
Clear the code and road test, then recheck for the code returning

How to fix

Repair or replace the open or damaged section of wiring
Clean, repair or replace corroded or damaged connectors and terminals
Replace any sensor found to be faulty on the shared supply
Restore poor earth or power supply connections to the control unit
Replace or repair the control unit only after wiring and sensors are proven good, and as the manufacturer specifies

Can I keep driving?

Medium severity

The car may run in limp mode and could stall or respond unpredictably, so avoid driving it other than a short trip to get it repaired. Have it checked soon, as the loss of sensor supply can affect safety and drivability.

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