P06A3

What it means

P06A3 is a generic code meaning the powertrain control module has detected an open circuit on sensor reference voltage circuit D. This is one of the regulated supplies (commonly 5 volts) that the module sends to sensors, and the module saw the voltage or current on that supply was outside the expected range, consistent with a break in the circuit. Which sensors share reference D depends on the vehicle and the wiring diagram, so the exact affected sensors vary by model and engine.

Symptoms

• Engine warning light on
• Poor or erratic running, or reduced power (limp mode)
• Rough idle or hesitation
• Other sensor codes stored at the same time, such as signal circuit low or implausible readings
• Difficulty starting or stalling in some cases
• Reduced fuel economy

Possible causes

• Open circuit, chafed or broken wire in the reference voltage D supply wire or its brancheslikely
• Corroded, loose or pushed-out pins in a connector on the reference D circuit or at a sensor on that circuitlikely
• Faulty sensor on the shared reference circuit causing the supply to read out of range (internal open or short)possible
• Poor connection or damage at the powertrain control module connectorpossible
• Water ingress or previous repair damage to the wiring loompossible
• Internal fault in the powertrain control module reference voltage supplyrare

How to diagnose

1. Read all stored codes and freeze frame data, noting any other sensor circuit codes that point to the shared sensors
2. Look up the wiring diagram for your vehicle to identify which sensors are fed by reference voltage D
3. Visually inspect the wiring and connectors for chafing, corrosion, water ingress, damage or poor previous repairs
4. Check live data for the affected sensors to see which read zero, implausible or fixed values
5. With the ignition on, unplug each sensor on the circuit in turn and measure the reference voltage at the connector, comparing with the specified value
6. Carry out a continuity and resistance check of the reference wire from the module to each sensor, with the module disconnected, and check for shorts to earth or other circuits
7. Check the module connector pins for tightness, corrosion and spread terminals
8. If wiring and sensors are all sound and the supply is still missing, consult the manufacturer procedure before suspecting the module

How to fix

• Repair or replace the damaged or open section of wiring, using proper soldered and sealed joints or the correct connector kit
• Clean, repair or replace corroded or loose connector terminals and ensure the connectors are fully seated
• Replace any sensor found to be faulty on the shared reference circuit
• Repair water ingress and secure the loom clear of heat and sharp edges
• Repair or replace the powertrain control module only after all other causes are excluded, following manufacturer procedures, and clear the code and road test to confirm

Can I keep driving?

Nearby codes

• P06A2GenericVariable A/C Compressor Control Circuit High
• P06A4GenericSensor Reference Voltage D Circuit Low