Actuator Supply Voltage Circuit High
The P0659 code indicates that the Powertrain Control Module (PCM) has detected a voltage higher than the specified range on the actuator supply voltage circuit. This circuit provides power to various actuators such as throttle actuator, variable valve timing solenoids, and transmission solenoids. A high voltage condition can be caused by a faulty alternator overcharging the system, a short to voltage in the wiring, or a malfunctioning PCM. This can lead to erratic actuator operation and potential damage to sensitive electronic components.
01. Most Common Causes
- Faulty alternator overcharging the battery
- Short to battery voltage in the actuator supply circuit
- Damaged PCM or internal short
- Corroded or loose connector at PCM or actuators
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Erratic transmission shifting or harsh engagement
- Reduced engine performance or stalling
- Actuators not functioning properly (e.g., throttle, VVT)
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to retrieve all stored codes and freeze frame data.
Step 2: Inspect the battery voltage with the engine running; should be 13.5-14.5V. If higher, test alternator.
Step 3: Visually inspect the actuator supply voltage circuit wiring and connectors for damage, corrosion, or shorts.
Step 4: With key on engine off, measure voltage at the actuator supply circuit; should be battery voltage. If higher than 15V, suspect a short to voltage.
Step 5: If wiring and alternator are okay, test the PCM for internal faults or perform a PCM reset.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive with this code as high voltage can damage sensitive electronic components and cause unpredictable vehicle behavior. Have it diagnosed promptly.
How much does it cost to fix?▼
The cost varies depending on the cause. Alternator replacement can be $200-$400, wiring repairs $100-$200, and PCM replacement $500-$1000. Diagnostic fees are typically $100-$150.