Cylinder 8 Deactivation/Intake Valve Control Circuit High
The P3460 code indicates that the powertrain control module (PCM) has detected a high voltage condition in the cylinder 8 deactivation/intake valve control circuit. This circuit controls the oil flow to the valve lifters for cylinder deactivation (e.g., Active Fuel Management or Displacement on Demand). A high voltage reading suggests a short to power, open circuit, or faulty component in the solenoid or wiring.
1. Most Common Causes
- Short to battery voltage (B+) in the wiring of cylinder 8 intake valve solenoid
- Damaged intake valve control solenoid or internal resistance out of specification
- Fault in the multiple valve control module (e.g., lifter oil manifold assembly in GM systems or equivalent)
- Moisture or corrosion in the solenoid circuit connector or wiring
- Intermittent ECM/PCM failure (less common, requires verification)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine misfire or rough idle
- Reduced fuel economy
- Loss of power or hesitation
- Cylinder deactivation system inoperative
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect the wiring and connector for cylinder 8 deactivation solenoid for damage, corrosion, or loose pins.
Step 3: Use a multimeter to check the solenoid resistance (typically 20-30 ohms) and compare to specs.
Step 4: Check for voltage at the solenoid connector with key on; should be battery voltage on one pin and ground on the other.
Step 5: If voltage is present but solenoid is faulty, replace the solenoid. If no voltage, trace circuit for open/short and repair as needed.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as the engine may misfire, causing catalytic converter damage or reduced performance. Short trips to a repair shop are acceptable.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for diagnosis and repair, depending on whether the solenoid or wiring needs replacement. Parts are usually $30-$80, labor $50-$100.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.