Cylinder 8 Deactivation/Intake Valve Control Circuit Low
The P3459 code indicates a low voltage condition in the cylinder 8 deactivation/intake valve control circuit. This circuit is part of the cylinder deactivation system (e.g., Active Fuel Management or Variable Cylinder Management) that shuts down cylinders to improve fuel economy. A low voltage reading suggests a short to ground, open circuit, or faulty component in the solenoid or wiring for cylinder 8's intake valve control.
1. Most Common Causes
- Faulty cylinder 8 deactivation solenoid
- Short to ground in wiring or connector
- Open circuit in the control circuit
- Engine control module (ECM) failure
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced fuel economy
- Engine misfire or rough idle
- Loss of power or hesitation
3. Step-by-Step Diagnosis
Step 1: Scan for additional codes and freeze frame data.
Step 2: Visually inspect wiring and connector for cylinder 8 deactivation solenoid for damage, corrosion, or loose connections.
Step 3: Test the solenoid resistance with a multimeter (compare to specifications).
Step 4: Check for voltage at the solenoid connector with the engine running (should see battery voltage).
Step 5: If wiring and solenoid are okay, test the ECM output or replace the ECM.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as it can cause misfires, reduced fuel economy, and potential catalytic converter damage. Have it diagnosed promptly.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for diagnosis and repair, but can be higher if the ECM needs replacement.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.