Exhaust Valve Control Solenoid Circuit Malfunction (Bank 2)
The P0084 code indicates a problem in the electrical circuit of the exhaust valve control solenoid on bank 2 of the engine. This solenoid is part of the variable valve timing (VVT) system, which adjusts exhaust valve timing to optimize performance and emissions. The powertrain control module (PCM) detects an abnormal voltage or resistance in the solenoid circuit, often due to a faulty solenoid, wiring issues, or a failed PCM. This can lead to reduced engine performance, increased emissions, and potential drivability issues.
1. Most Common Causes
- Faulty or damaged exhaust variable valve timing (EVVT) solenoid
- Wiring issues: short to ground, short to voltage, or open circuit in the solenoid circuit
- Corroded, loose, or damaged solenoid connector
- Solenoid internal resistance out of specification
- Faulty circuit relay (if applicable)
- Engine control module (ECM/PCM) problem (less common)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Rough idle or engine misfire
- Reduced engine power and fuel economy
- Failed emissions test
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 damage, corrosion, or loose connections.
Step 3: Test the solenoid resistance with a multimeter (compare to manufacturer specs).
Step 4: Check for battery voltage and ground at the solenoid connector with the ignition on.
Step 5: If wiring and solenoid are okay, test the PCM output signal (may require advanced diagnostics).
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as it can cause reduced performance and potential engine damage. Have it diagnosed promptly.
How much does it cost to fix?▼
Typically $50-$150 for diagnosis and solenoid replacement, but costs vary by vehicle and labor rates.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.