Cylinder 9 Exhaust Valve Control Circuit Low
The P3471 code indicates that the powertrain control module (PCM) has detected a low voltage condition in the exhaust valve control circuit for cylinder 9. This circuit is responsible for controlling the exhaust valve timing or lift, often in engines with variable valve timing (VVT) or cylinder deactivation systems. A low voltage signal suggests a short to ground, open circuit, or faulty component, which can disrupt valve operation and cause performance issues.
1. Most Common Causes
- Faulty or internally shorted cylinder 9 exhaust valve control solenoid
- Wiring circuit shorted to ground or with excessive resistance
- Corroded, bent, or poorly connected electrical connector
- Open or defective power supply relay or fuse for the circuit
- Internal failure in the powertrain control module (PCM)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine misfire or rough idle
- Reduced engine power or performance
- Poor fuel economy
3. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for additional codes.
Step 2: Visually inspect the wiring and connector for cylinder 9 exhaust valve control solenoid for damage, corrosion, or loose connections.
Step 3: Test the solenoid resistance with a multimeter and compare to manufacturer specifications.
Step 4: Check for voltage at the solenoid connector with the engine running; if low, trace the circuit for shorts or opens.
Step 5: If wiring and solenoid are good, suspect a PCM issue and perform further diagnostics.
4. 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 performance, and potential damage to the catalytic converter or engine components.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for diagnosis and repair, depending on the cause. Replacing a solenoid may cost $100-$200, while wiring repairs are usually less.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.