P0085
UniversalExhaust Valve Control Circuit Low (Bank 2)
Medium SeverityThis code indicates an electrical issue where the voltage in the exhaust valve control circuit on engine bank 2 is lower than expected. This fault typically impairs the variable valve timing system, leading to suboptimal engine performance and reduced fuel efficiency.
⚠️ Before You Begin (Safety First)
Always disconnect the battery before performing any electrical work on your vehicle. Ensure the engine is cool before handling components, and be cautious around hot exhaust parts and moving belts. Wear appropriate personal protective equipment, including gloves and eye protection.
Common Symptoms
- Check Engine Light illumination
- Reduced engine power or acceleration
- Rough idle or stalling
- Decreased fuel economy
- Possible increase in exhaust emissions
Common Causes
- Faulty exhaust VVT solenoid on Bank 2
- Open or short to ground in the wiring harness to the solenoid
- Corroded or loose electrical connector for the solenoid
- Insufficient oil pressure or dirty engine oil (less common for 'circuit low' but can impact VVT function)
- Failed Engine Control Module (ECM)
Frequently reported on: General/Universal V6/V8 Engines with VVT
Diagnostic Steps
- Retrieve and record all stored OBD-II codes and freeze frame data.
- Visually inspect the wiring harness and electrical connector for the exhaust VVT solenoid on Bank 2 for any signs of damage, corrosion, or looseness.
- Check the resistance of the exhaust VVT solenoid on Bank 2 using a multimeter. Compare the reading to factory specifications.
- Test for proper voltage supply and ground at the solenoid connector using a multimeter while the ignition is on.
- If tests indicate a faulty solenoid, replace the exhaust VVT solenoid on Bank 2.
- Clear the trouble code and perform a test drive to confirm the repair.
👨🔧 When to Call a Professional
If you have checked the wiring, connectors, and replaced the exhaust VVT solenoid without resolving the P0085 code, or if you lack specialized electrical diagnostic tools, it is best to consult a professional mechanic. They can perform advanced circuit testing and rule out a potential Engine Control Module (ECM) issue.
Commonly Asked Questions
What does 'Bank 2' refer to?
Bank 2 refers to the cylinder bank on V-type engines that does not contain cylinder number one. For inline engines, there is typically only one bank.
Is it safe to drive with a P0085 code?
While you might be able to drive the vehicle, it's not recommended for extended periods. The code indicates a problem with engine timing that can lead to reduced performance, poor fuel economy, and potentially cause further engine damage or increase emissions over time.
How do I locate the exhaust VVT solenoid on Bank 2?
The exhaust VVT solenoid is usually located on the cylinder head, near the exhaust camshaft, on the Bank 2 side of the engine. Consult your vehicle's specific service manual or an online diagram for its precise location.
Can low oil cause a P0085 code?
While P0085 specifically points to an electrical circuit issue, the variable valve timing system relies on proper oil pressure and clean oil to function correctly. Extremely low or dirty oil can indirectly affect VVT performance, though a 'circuit low' code more often indicates an electrical fault with the solenoid or wiring.
Could the Engine Control Module (ECM) be the cause?
Yes, an ECM malfunction could cause a P0085 code, but it is typically a rare cause. You should thoroughly check the solenoid and all associated wiring and connectors before suspecting the ECM.