P0085 Exhaust Valve Control Solenoid Circuit Low (Bank 2)

The P0085 trouble code means that the engine control module (ECM/PCM) has detected a low electrical signal in the exhaust valve control solenoid circuit on Bank 2.

This system is generally part of the engine's variable valve timing (VVT) or variable valve lift/control system. The exhaust valve control solenoid regulates oil flow to the mechanism that changes exhaust camshaft timing or valve operation according to engine speed and load.

Because P0085 specifically identifies a circuit low condition, the problem is often electrical rather than purely mechanical. However, an engine oil problem, a sticking solenoid, or a mechanical VVT fault can sometimes contribute to the condition.

What Does Bank 2 Mean?

Bank 2 is the cylinder bank that does not contain cylinder number 1.

On V6 and V8 engines, there are normally two cylinder banks, so the engine can have a Bank 1 and Bank 2 exhaust valve control solenoid.

On an inline four-cylinder engine, there is normally only one cylinder bank, so a Bank 2 code generally does not apply.

The exact location of the Bank 2 exhaust valve control solenoid varies by engine design.

What Is the Exhaust Valve Control Solenoid?

The exhaust valve control solenoid is commonly associated with the engine's variable valve timing system.

The ECM controls the solenoid electrically. The solenoid then regulates engine oil flow to a camshaft actuator or related mechanism.

This allows the engine to alter exhaust valve timing according to operating conditions.

For example, the engine may use different camshaft timing during:

• Cold starting

• Idle

• Low-speed driving

• Acceleration

• High engine speed

• Heavy engine load

Changing valve timing can improve power, fuel economy, emissions, and engine smoothness.

What Does “Circuit Low” Mean?

The word “low” refers primarily to the electrical signal in the control circuit.

The ECM expects to see a particular electrical behavior from the exhaust valve control solenoid.

If the voltage or current in the circuit is lower than the expected range, the ECM may store P0085.

A circuit-low condition can be caused by:

• Short to ground

• Damaged wiring

• Faulty solenoid

• Internal solenoid short

• Poor electrical connection

• Connector damage

• Control-circuit problem

• ECM driver fault

Therefore, P0085 should not automatically be interpreted as a mechanical camshaft problem.

Common Causes of P0085

Faulty exhaust valve control solenoid

The solenoid itself may have an internal electrical fault.

Its coil can become damaged, shorted, open, or contaminated by engine oil deposits.

A mechanically stuck solenoid can also prevent proper operation.

Shorted wiring

A wire in the control circuit may be contacting ground.

This can pull the circuit voltage down and trigger P0085.

Damaged wiring

The harness can become damaged because of:

• Engine vibration

• Heat

• Oil contamination

• Chafing

• Previous repairs

• Contact with other components

Connector problems

Corrosion, loose terminals, water intrusion, or damaged connector pins can interfere with the solenoid circuit.

Low engine oil level

The variable valve timing system generally depends on engine oil pressure.

If the oil level is too low, the VVT mechanism may not operate correctly.

Low oil pressure can also cause related valve-timing problems.

Dirty or incorrect engine oil

Old, contaminated, or incorrect-viscosity oil can interfere with the operation of a VVT solenoid.

Oil passages and the solenoid's internal screen can become restricted.

Blocked oil passage

The solenoid controls oil flow to the camshaft actuator.

If the oil passage is restricted, the system may not be able to achieve the commanded camshaft position.

Faulty camshaft actuator

The camshaft phaser or actuator can become stuck or mechanically damaged.

In this situation, the electrical solenoid may be functioning but the mechanical VVT mechanism may not respond correctly.

ECM/PCM problem

A faulty ECM control driver is possible, but this should be considered only after the solenoid and wiring have been properly tested.

Symptoms of P0085

The symptoms can vary depending on the engine and the severity of the fault.

Possible symptoms include:

• Check Engine Light

• Rough idle

• Poor acceleration

• Reduced engine power

• Poor fuel economy

• Engine hesitation

• Difficult starting

• Unstable idle

• Reduced engine performance

• Increased emissions

• Engine stalling in some cases

Some vehicles may continue to drive almost normally if the ECM disables the variable valve timing function and uses a fixed camshaft position.

Can P0085 Affect Engine Performance?

Yes.

Variable valve timing allows the engine to optimize valve operation under different conditions.

If the Bank 2 exhaust valve control system cannot operate correctly, the engine may lose some of its ability to optimize combustion.

The driver may notice reduced performance, especially during acceleration or at certain engine speeds.

However, the severity depends on the specific engine strategy.

How Is P0085 Diagnosed?

A proper diagnosis should begin with a complete scan of the vehicle.

Check for:

• Stored DTCs

• Pending DTCs

• Freeze-frame data

• Other VVT codes

• Camshaft position codes

• Engine oil-related issues

Other codes involving the camshaft position sensors, crankshaft position sensor, or variable valve timing system can provide important clues.

Check the Engine Oil First

Before performing complicated electrical tests, check the engine oil.

Verify:

• Oil level

• Oil condition

• Correct oil viscosity

• Correct oil specification

• Evidence of contamination

If the oil is extremely dirty or the level is very low, the VVT system may not operate correctly.

However, simply changing the oil should not be considered a complete repair unless the oil condition was actually the cause.

Inspect the Solenoid Connector and Wiring

The Bank 2 exhaust valve control solenoid and its wiring should be inspected carefully.

Look for:

• Broken wires

• Melted insulation

• Chafing

• Oil-soaked wiring

• Corroded terminals

• Loose connector pins

• Water intrusion

• Poor previous repairs

The wiring should be checked for continuity and shorts according to the manufacturer's procedure.

Test the Solenoid

The exhaust valve control solenoid should be electrically tested.

Depending on the system, testing can include checking:

• Coil resistance

• Power supply

• Ground/control circuit

• ECM control signal

• Connector condition

The resistance specification is engine-specific.

A resistance value that is considered normal on one solenoid may be incorrect for another.

If the solenoid passes electrical tests, its mechanical operation should also be considered.

Check for a Short to Ground

Because P0085 identifies a low circuit condition, checking for an unintended connection to ground is particularly important.

A damaged control wire may be touching:

• Engine metal

• Chassis ground

• Another grounded component

• Damaged wiring insulation

This can pull the solenoid control circuit low.

The exact test method depends on whether the system uses a high-side or low-side ECM driver.

Check the VVT Oil Passages

If the electrical circuit is functioning correctly, the mechanical side of the system should be investigated.

Check for:

• Restricted oil passages

• Dirty VVT solenoid screens

• Sludge

• Sticking components

• Insufficient oil pressure

A variable valve timing system cannot operate correctly if the required oil flow is unavailable.

Check Actual vs. Commanded Camshaft Position

Advanced scan tools can often display:

Commanded camshaft position vs. actual camshaft position

If the ECM commands a change but the camshaft does not respond as expected, the problem may involve:

• VVT solenoid

• Oil pressure

• Oil passages

• Camshaft actuator

• Mechanical timing

• Camshaft position sensor

This information can be very useful in separating an electrical problem from a mechanical VVT problem.

Check the Camshaft Position Sensor

The camshaft position sensor itself is not the same component as the exhaust valve control solenoid.

However, the ECM uses camshaft position information to verify whether the commanded valve timing change actually occurred.

A faulty camshaft position sensor or damaged wiring can therefore produce additional timing-related trouble codes.

If related camshaft sensor codes are present, they should be diagnosed as part of the same system.

P0085 and Engine Timing

P0085 does not necessarily mean that the engine's basic mechanical timing has jumped.

However, a problem with the VVT system can cause the effective camshaft timing to be incorrect.

If the engine has additional timing-related codes, mechanical timing should be checked according to the manufacturer's procedure.

P0085 vs. P0075

These codes are similar but refer to different engine banks.

P0075 — Intake Valve Control Solenoid Circuit, Bank 1

P0085 — Exhaust Valve Control Solenoid Circuit Low, Bank 2

The exact terminology can vary slightly between manufacturers, but P0085 generally points toward the Bank 2 exhaust valve control circuit.

P0085 vs. P0086

These codes concern the same general system but identify different electrical conditions.

P0085 — Exhaust Valve Control Solenoid Circuit Low, Bank 2

P0086 — Exhaust Valve Control Solenoid Circuit Range/Performance, Bank 2

P0085 specifically points toward a low electrical circuit condition, while P0086 indicates that the circuit or solenoid is operating outside its expected range or performance.

P0085 vs. P0087

P0085 and P0087 are unrelated despite the similar numbers.

P0085 concerns the Bank 2 exhaust valve control solenoid circuit.

P0087 generally concerns fuel rail/system pressure being too low.

They involve completely different systems.

Can Low Engine Oil Cause P0085?

It can contribute to VVT problems, although a low-oil condition does not necessarily create the electrical circuit-low condition by itself.

The VVT system relies on engine oil for hydraulic operation.

If oil pressure or oil flow is insufficient, the camshaft actuator may fail to respond correctly.

Therefore, when P0085 appears together with camshaft timing or VVT performance codes, engine oil level and condition should be checked.

Can P0085 Damage the Engine?

P0085 itself does not necessarily mean immediate engine damage.

However, the underlying problem can be important.

If the fault is simply a damaged electrical wire, the engine may continue to operate with relatively little risk.

If the problem involves:

• Severe oil starvation

• Mechanical timing failure

• Camshaft actuator failure

• Significant internal engine wear

then continued driving could lead to more serious problems.

A vehicle with severe engine noise, major power loss, stalling, or an oil-pressure warning should not continue to be driven until the cause is determined.

Can You Drive With P0085?

Short-term driving may be possible if the engine runs normally and the Check Engine Light remains steady.

However, the fault should be diagnosed as soon as possible.

Avoid continued driving if the vehicle has:

• Severe rough running

• Significant loss of power

• Engine knocking or abnormal mechanical noise

• Oil-pressure warning

• Repeated stalling

• Flashing Check Engine Light

These symptoms may indicate a more serious engine problem than the P0085 code alone suggests.

How Is P0085 Repaired?

The repair depends on the confirmed cause.

Possible repairs include:

• Replacing the Bank 2 exhaust valve control solenoid

• Repairing a shorted control wire

• Repairing damaged wiring

• Replacing a damaged connector

• Correcting poor electrical connections

• Replacing contaminated or incorrect engine oil

• Cleaning a restricted VVT oil passage

• Repairing or replacing the camshaft actuator

• Correcting an oil-pressure problem

• Repairing the ECM control circuit when properly confirmed

The code should be cleared after the repair and the vehicle should be tested to confirm that the VVT system operates correctly.

Should You Replace the VVT Solenoid Immediately?

No.

P0085 is often associated with the valve control solenoid, but replacing it without testing can result in an unnecessary repair.

Because the code specifically identifies a low electrical circuit condition, the wiring and electrical circuit deserve particular attention.

A useful diagnostic order is:

Check oil → scan all codes → inspect connector → inspect wiring → test solenoid → check control circuit → verify oil flow/pressure → check VVT actuator and camshaft position.

Final Takeaway

P0085 Exhaust Valve Control Solenoid Circuit Low (Bank 2) indicates that the ECM/PCM has detected a low electrical condition in the Bank 2 exhaust valve control solenoid circuit.

The most common areas to investigate include the VVT solenoid, wiring, connector, power/control circuit, engine oil condition, oil passages, and camshaft actuator.

Because the code specifically indicates a circuit-low condition, an electrical fault should be considered before assuming that the mechanical VVT system has failed.

Most importantly, P0085 does not automatically mean that the exhaust valve control solenoid must be replaced. Proper electrical testing and inspection can distinguish a failed solenoid from a wiring problem, while oil-pressure and mechanical checks can identify problems deeper within the variable valve timing system.