P0659

What it means

P0659 is the generic code for Actuator Supply Voltage 'A' Circuit High. The powertrain control module monitors the supply voltage it provides to an actuator circuit and has seen it higher than expected, or a fault in the driver or supply circuit that causes a high reading. Which actuators sit on supply 'A' depends on the vehicle, so the affected components vary by model and engine.

Symptoms

• Engine warning light on
• Engine running in limp mode or with reduced power
• Rough idle or misfire
• Actuator-controlled systems not working, such as throttle, variable valve timing or EGR
• Poor starting or stalling
• Other related fault codes stored alongside

Possible causes

• Short to voltage in the wiring of the actuator supply circuitlikely
• Corroded, damaged or loose connector terminals on the actuator or control modulelikely
• Faulty actuator with an internal fault pulling the supply circuit highpossible
• Charging system fault causing overvoltage, such as a failing alternator regulatorpossible
• Faulty relay or fuse circuit feeding the actuators, with a wiring fault on the supply sidepossible
• Internal fault in the powertrain control module or its driver circuitrare
• Outdated control module software where the manufacturer has documented a fixrare

How to diagnose

1. Read all stored codes and freeze frame data, noting engine speed, load and battery voltage when the code set, and check for related actuator codes.
2. Check the battery voltage with the engine off and running; charging voltage should be within the manufacturer's specification and not excessive.
3. Inspect the wiring, connectors and fuses for the actuator supply circuit for chafing, heat damage, water ingress, corrosion and bent or pushed-back pins.
4. Using the wiring diagram for the specific model, identify which actuators share supply 'A' and the relay that feeds them.
5. Check the relay and its output supply with a multimeter, looking for voltage present when it should be off or higher than battery voltage.
6. Unplug the actuators on the circuit one at a time and see whether the fault clears or the supply voltage returns to normal.
7. Test for a short to voltage on the circuit wiring with the module disconnected, following the manufacturer's procedure.
8. Check for software updates or technical bulletins for the model and fault code, and only then consider the control module.

How to fix

• Repair or replace damaged wiring and fix any short to voltage in the supply circuit.
• Clean or replace corroded or damaged connectors and terminals.
• Replace the faulty actuator that is causing the high supply voltage.
• Repair or replace the alternator or regulator if the charging voltage is too high.
• Replace a faulty relay or related supply component.
• Update or repair the control module software or replace the module only if testing confirms it is faulty.

Can I keep driving?

Nearby codes

• P0658GenericActuator Supply Voltage A Circuit Low
• P065AGenericGenerator System Performance