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 is responsible for controlling the oil flow to the valve lifters that deactivate the cylinder's intake valves during low-load operation to improve fuel economy. A high voltage reading suggests a short to power, open circuit, or faulty component in the solenoid or wiring.
01. Most Common Causes
- Faulty cylinder deactivation solenoid on cylinder 8
- Short to voltage in the wiring or connector
- Open circuit in the control circuit
- Corroded or damaged connector pins
- Failed PCM (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced fuel economy
- Engine misfire or rough idle
- Loss of power or hesitation
- Cylinder deactivation system inoperative
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to retrieve freeze frame data and confirm the code.
Step 2: Visually inspect the 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 manufacturer specs (typically 10-20 ohms).
Step 4: Check for voltage at the solenoid connector with the engine running; should be battery voltage when commanded on.
Step 5: If wiring and solenoid are good, test the PCM output circuit for continuity and shorts.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as the cylinder deactivation system may not function, reducing fuel economy, and the engine may misfire, potentially causing catalytic converter damage.
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 PCM needs replacement.