Cylinder 12 Exhaust Valve Control Circuit Low
The P3495 code indicates that the powertrain control module (PCM) has detected a low voltage condition in the exhaust valve control circuit for cylinder 12. This circuit is responsible for controlling the exhaust valve timing or lift, often via an electrohydraulic or electromechanical actuator. A low voltage reading suggests a short to ground, open circuit, or faulty component, which can disrupt valve operation and cause performance issues.
01. Most Common Causes
- Faulty exhaust valve control solenoid/actuator on cylinder 12
- Short to ground in the control circuit wiring
- Open circuit or high resistance in the wiring or connector
- Failed PCM (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine misfire or rough idle
- Reduced engine power and fuel economy
- Possible engine knocking or hesitation
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to confirm the code and check for related codes (e.g., P3496 for high voltage).
Step 2: Visually inspect the wiring and connector for cylinder 12 exhaust valve control circuit for damage, corrosion, or loose connections.
Step 3: Measure voltage and resistance at the actuator connector with a multimeter; compare to manufacturer specifications.
Step 4: Test the actuator by applying battery voltage and ground (if safe) to see if it clicks; replace if faulty.
Step 5: If wiring and actuator are good, suspect a PCM issue; perform a PCM reflash or replacement as last resort.
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 issue can cause engine misfire, reduced power, and potential catalytic converter damage. Have it diagnosed promptly.
How much does it cost to fix?▼
Diagnosis typically costs $50-$150. Repair costs vary: a new actuator may be $100-$300, plus labor. Wiring repairs are usually under $200.