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P0659 – Actuator Supply Voltage Circuit High (OBD2)

P0659 means "Actuator Supply Voltage Circuit High". The voltage in the sensor reference voltage circuit circuit is above the permitted maximum. For most sensors this points to an open signal or ground wire – the signal "floats" up to the reference voltage – or to a short to voltage.

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P0659 quick summary

Fault codeP0659
MeaningActuator Supply Voltage Circuit High
SystemPowertrain (Engine & Transmission)
VehiclesGeneric OBD2
SeverityHigh
Can I drive?Not recommended. Several sensors fail at once, usually with limp mode, stalling or no start.
Repair cost€0 – €500

What the sensor reference voltage is

The control unit supplies a stable 5 V reference to many sensors; these codes mean one of the reference circuits (A, B or C) or the actuator supply voltage is shorted or open.

Sensors such as MAP, throttle position, pedal position, rail pressure and camshaft sensors receive a 5 V reference from the control unit. To limit the effect of a fault, the control unit usually has several separate reference circuits (A, B, C), each supplying a group of sensors. P0657–P0659 cover the separate supply for actuators.

If one sensor or wire shorts the reference to ground, the voltage drops and every sensor on that circuit fails at once. That is why reference voltage codes often come with many other sensor codes and limp mode.

The quickest way to find the fault is to unplug the sensors on the affected circuit one by one while watching the reference voltage: when it recovers, you have found the shorted sensor.

On VAG vehicles (VW, Audi, Škoda, Seat, Cupra), VCDS and older VAG testers can show this code as the five-digit VAG code 17043 (P0659). Both numbers mean the same fault.

Symptoms of P0659

  • Several sensor codes at the same time
  • Limp mode or no start
  • Throttle or pedal not responding
  • Engine stalls
  • Check Engine and EPC lights on

Most common causes of P0659 (most likely first)

Mechanic's Pro Tip

Do not replace the control unit for a reference voltage code until every sensor on that circuit has been unplugged and tested. A single faulty sensor is by far the most common cause.

  1. 1.Open circuit in the signal or ground wire

    Most likely

    A loose ground connection is a very common cause.

  2. 2.Signal wire shorted to the 5 V reference or battery voltage

  3. 3.Faulty sensor reference voltage circuit

  4. 4.Water in a connector

  5. 5.Control unit reference output fault

Step-by-step diagnostic guide

  1. 1

    Read codes

    Read all codes and list which sensors report faults – they share the affected reference circuit.

  2. 2

    Check signal and ground

    With the ignition on and the sensor reference voltage circuit plugged in, back-probe the signal and ground wires. A signal stuck at reference or battery voltage points to an open ground/signal wire or a short to voltage.

    Multimeter: Ground wire to battery negative: below about 0.1 V. Signal stuck at about 5 V (or 12 V) = open or short to voltage.

  3. 3

    Measure the reference voltage

    Measure the reference at one of the sensors.

    Multimeter: Normal: about 4.9–5.1 V. Near 0 V = short to ground; above 5 V = short to voltage.

  4. 4

    Unplug sensors one by one

    While measuring, unplug each sensor on the circuit. When the reference recovers, that sensor (or its wiring) is the cause.

  5. 5

    Inspect wiring

    If unplugging sensors does not help, inspect the harness for chafing and shorts.

  6. 6

    Repair and clear

    Replace the shorted sensor or repair the wire, then clear codes.

Frequently asked questions

Can I keep driving with P0659?

Not recommended. Several sensors fail at once, usually with limp mode, stalling or no start.

How much does it cost to fix P0659?

Typical repair costs are 0 € – 500 €, depending on the cause and the vehicle. The most common fixes are: open circuit in the signal or ground wire; signal wire shorted to the 5 V reference or battery voltage; faulty sensor reference voltage circuit. Always confirm the cause with the tests above before buying parts.

Why do I have so many sensor codes at once?

Because several sensors share the same 5 V reference. If it fails, they all report faults together.

Can a bad sensor damage the control unit?

Control units are protected, but a long-term short can damage the reference output. Fix it promptly.

What is the difference between P0659 and similar codes?

P0659 belongs to a group of codes for the same component that differ in the type or location of the fault: P0653 – Sensor Reference Voltage B Circuit High; P0657 – Actuator Supply Voltage Circuit / Open; P0658 – Actuator Supply Voltage Circuit Low; P0697 – Sensor Reference Voltage C Circuit / Open; P0698 – Sensor Reference Voltage C Circuit Low; P0699 – Sensor Reference Voltage C Circuit High. The tests on this page apply to the whole group; the type of fault tells you where to start.

Related fault codes

This guide is for information only. Working on vehicles can be dangerous — if you are unsure, have the car checked by a qualified mechanic. Values can differ between model years; always check the manufacturer's repair information.