P0085 Exhaust valve control solenoid circuit low (Bank 2)

Introduction:

The P0085 diagnostic trouble code (DTC) indicates a problem with the exhaust valve control solenoid circuit on Bank 2 of your engine. This circuit is crucial for the proper functioning of Variable Valve Timing (VVT) systems, which enhance engine performance and fuel efficiency. Understanding the causes, symptoms, and diagnostic procedures for P0085 is essential for accurate troubleshooting and repair.

Comprehensive Table: P0085 Exhaust Valve Control Solenoid Circuit Low (Bank 2)

Topic	Description	Potential Impact
Definition	Exhaust Valve Control Solenoid Circuit Low (Bank 2) indicates that the Engine Control Unit (ECU) has detected a lower-than-expected voltage in the control circuit for the exhaust valve control solenoid on Bank 2. Bank 2 refers to the side of the engine opposite cylinder #1.	Reduced engine performance, decreased fuel economy, potential engine damage if the VVT system is unable to function correctly.
Common Causes	- Faulty exhaust valve control solenoid (Bank 2) - Open or shorted wiring in the exhaust valve control solenoid circuit (Bank 2) - Poor electrical connection in the exhaust valve control solenoid circuit (Bank 2) - Faulty Engine Control Unit (ECU) (rare) - Low engine oil level or pressure - Blocked oil passages to the VVT system - Timing chain issues (stretched or worn) - Incorrect engine oil viscosity - Debris or contamination in the oil affecting solenoid operation - Failure of the VVT actuator itself	Poor engine performance, rough idling, stalling, increased emissions, potential catalytic converter damage. Long-term neglect can lead to more severe engine problems.
Symptoms	- Check Engine Light (CEL) illumination - Reduced engine power - Poor fuel economy - Rough idling - Stalling - Hesitation during acceleration - Engine knocking or ticking noises - Failed emissions test - Engine running rich or lean (depending on the specific VVT system and failure mode)	Driver discomfort, inconvenience, increased running costs. Potential for secondary damage to other engine components if the root cause is not addressed promptly.
Diagnostic Steps	1. Verify the code with a scan tool. 2. Visually inspect the wiring and connectors to the exhaust valve control solenoid on Bank 2. 3. Check the solenoid's resistance using a multimeter. 4. Check the voltage at the solenoid connector with the engine running. 5. Inspect engine oil level and condition. 6. Perform a VVT system test using a scan tool (if available). 7. Check for any relevant Technical Service Bulletins (TSBs). 8. Use an oscilloscope to examine the solenoid's control signal. 9. Perform a compression test to rule out mechanical issues. 10. Check the timing chain for proper tension and wear.	Accurate diagnosis leads to effective repair and prevents misdiagnosis. Thoroughness is crucial for identifying the underlying cause.
Troubleshooting Wiring Issues	- Inspect wiring for damage (chafing, cuts, burns). - Check connectors for corrosion or loose pins. - Use a multimeter to test for continuity and shorts in the wiring. - Perform a voltage drop test to identify areas of high resistance. - Refer to wiring diagrams for accurate circuit tracing. - Use dielectric grease on connectors to prevent corrosion.	Prevents unnecessary component replacement. Addresses intermittent issues caused by wiring problems.
Testing the Solenoid	- Disconnect the solenoid connector. - Use a multimeter to measure the resistance of the solenoid coil. - Compare the measured resistance to the manufacturer's specifications. - Use a power probe to activate the solenoid and listen for a clicking sound. - Check for shorts to ground within the solenoid. - Visually inspect the solenoid for physical damage.	Determines if the solenoid is functioning correctly. Identifies internal failures within the solenoid.
Engine Oil Considerations	- Use the correct engine oil viscosity as specified by the manufacturer. - Ensure the engine oil level is within the acceptable range. - Change the engine oil and filter regularly. - Look for signs of sludge or contamination in the oil. - Check engine oil pressure with a mechanical gauge to confirm adequate pressure at the solenoid.	Proper lubrication is crucial for VVT system operation. Contaminated or low oil can impair solenoid function.
Scan Tool Diagnostics	- Use a scan tool to monitor VVT system parameters in real-time. - Check for any other related DTCs. - Perform output tests to activate the exhaust valve control solenoid. - Check the VVT system's adaptation values. - Use the scan tool to clear the DTC after repairs.	Provides valuable data for diagnosing VVT system issues. Allows for active testing of components.
Related Diagnostic Trouble Codes	P0080: Exhaust Valve Control Solenoid Circuit (Bank 1) P0081: Exhaust Valve Control Solenoid Circuit Range/Performance (Bank 1) P0082: Exhaust Valve Control Solenoid Circuit Low (Bank 1) P0083: Exhaust Valve Control Solenoid Circuit High (Bank 1) P0086: Exhaust Valve Control Solenoid Circuit Range/Performance (Bank 2) P0087: Fuel Rail/System Pressure - Too Low (Bank 1) P0088: Fuel Rail/System Pressure - Too High (Bank 1) P0010: "A" Camshaft Position Actuator Circuit (Bank 1) P0013: "B" Camshaft Position Actuator Circuit (Bank 1) P0016: Camshaft Position Correlation (Bank 1 Sensor A)	Understanding related codes can help pinpoint the root cause of the problem.
Repair Solutions	- Replace the faulty exhaust valve control solenoid (Bank 2). - Repair or replace damaged wiring and connectors. - Clean or replace clogged oil passages. - Replace the Engine Control Unit (ECU) (rare). - Perform an engine oil change with the correct viscosity. - Address timing chain issues. - Flush the engine to remove sludge or contaminants.	Restores proper VVT system function. Resolves the underlying cause of the P0085 code.

Detailed Explanations:

Definition: The P0085 code signals that the ECU has registered a voltage in the exhaust valve control solenoid circuit on Bank 2 that is lower than expected. This can happen due to various electrical or mechanical problems within the VVT system. "Bank 2" always refers to the cylinder bank that does not contain cylinder #1.

Common Causes: The most frequent culprits include a malfunctioning exhaust valve control solenoid itself, damaged wiring, poor electrical connections, or, less commonly, a faulty ECU. Low oil level/pressure, blocked oil passages feeding the VVT system, a stretched timing chain, or even the wrong engine oil viscosity can also contribute. Debris in the oil can also prevent the solenoid from operating correctly. Finally, internal failure of the VVT actuator (the device the solenoid controls) is another possibility.

Symptoms: The most noticeable symptom is the illumination of the Check Engine Light (CEL). Drivers might also experience reduced engine power, poor fuel economy, rough idling, stalling, or hesitation during acceleration. Engine knocking or ticking noises, particularly during cold starts, can also be indicative of VVT issues. A failed emissions test is another potential consequence. The engine might run either rich or lean depending on the specific VVT system design and the nature of the failure.

Diagnostic Steps: A systematic approach is essential. First, confirm the code with a scan tool. Then, visually inspect the wiring and connectors associated with the Bank 2 exhaust valve control solenoid for any signs of damage. Check the solenoid's resistance using a multimeter and compare it to the manufacturer's specifications. Verify the voltage present at the solenoid connector with the engine running. Inspect the engine oil level and condition. If available, perform a VVT system test using a scan tool. Check for any relevant Technical Service Bulletins (TSBs) issued by the vehicle manufacturer. An oscilloscope can be used to examine the solenoid's control signal. Perform a compression test to rule out mechanical issues before assuming the problem is solely electrical. Finally, inspect the timing chain for proper tension and wear, as a stretched chain can cause VVT malfunctions.

Troubleshooting Wiring Issues: Carefully examine the wiring harness for any signs of damage, such as chafing, cuts, or burns. Pay close attention to connectors, looking for corrosion or loose pins. Use a multimeter to test for continuity and shorts within the wiring. A voltage drop test can help pinpoint areas of high resistance. Consult wiring diagrams to accurately trace the circuit. Applying dielectric grease to connectors can help prevent future corrosion.

Testing the Solenoid: Begin by disconnecting the solenoid connector. Use a multimeter to measure the resistance of the solenoid coil. Compare this value to the manufacturer's specified range. Use a power probe to briefly activate the solenoid and listen for a distinct "clicking" sound, indicating that the solenoid is attempting to move. Check for any shorts to ground within the solenoid itself. Visually inspect the solenoid for any signs of physical damage.

Engine Oil Considerations: Always use the engine oil viscosity recommended by the vehicle manufacturer. Ensure that the oil level is within the acceptable range. Adhere to a regular oil change schedule. Inspect the drained oil for any signs of sludge or contamination. If possible, check the engine oil pressure with a mechanical gauge to confirm adequate pressure at the solenoid location.

Scan Tool Diagnostics: A scan tool can provide valuable data. Monitor VVT system parameters in real-time, such as camshaft and crankshaft angles. Check for any other related DTCs that might offer clues. Perform output tests to activate the exhaust valve control solenoid and observe its response. Check the VVT system's adaptation values, which can indicate long-term wear or adjustments. After completing repairs, use the scan tool to clear the DTC.

Related Diagnostic Trouble Codes: Understanding related codes can significantly aid in diagnosis. For example, P0080, P0081, P0082, and P0083 pertain to the exhaust valve control solenoid on Bank 1. P0086 covers Range/Performance issues on Bank 2. Codes like P0087 and P0088, related to fuel rail pressure, might indirectly impact VVT operation. Codes related to camshaft position actuators (P0010, P0013) or camshaft position correlation (P0016) can also be related to VVT malfunctions.

Repair Solutions: The appropriate repair depends on the identified cause. Replacing the faulty exhaust valve control solenoid (Bank 2) is a common solution. Repairing or replacing damaged wiring and connectors is essential for electrical issues. Cleaning or replacing clogged oil passages might be necessary if oil flow is restricted. Replacing the ECU is a rare but possible solution. Performing an engine oil change with the correct viscosity is crucial. Addressing timing chain issues, such as replacing a stretched chain, is important. Flushing the engine to remove sludge or contaminants can improve VVT system operation.

Frequently Asked Questions:

What does the P0085 code mean? It means the engine control unit (ECU) has detected a low voltage in the exhaust valve control solenoid circuit on Bank 2. This indicates a problem with the VVT system.
Can I drive with a P0085 code? It's generally not recommended. While the car may run, reduced engine performance and potential engine damage can occur if the VVT system is not functioning correctly.
How do I fix a P0085 code? Troubleshooting involves checking the solenoid, wiring, oil level, and VVT system. Repair solutions range from replacing the solenoid to repairing wiring or addressing oil-related issues.
Is the P0085 code serious? Yes, it can be. Ignoring the code can lead to reduced engine performance, poor fuel economy, and potential engine damage.
What is Bank 2? Bank 2 is the side of the engine opposite cylinder #1 in V-type engines.

Conclusion:

The P0085 code requires a systematic approach to diagnosis and repair, focusing on both electrical and mechanical components within the VVT system. Addressing the underlying cause promptly will ensure optimal engine performance and prevent potential long-term damage.