P0085
Exhaust Valve Control Solenoid Circuit Low (Bank 2)P0085 is a generic OBD-II powertrain diagnostic trouble code: Exhaust Valve Control Solenoid Circuit Low (Bank 2). It is logged by the engine control unit when the powertrain monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.
What P0085 means
P0085 is stored when the ECM detects a lower-than-expected voltage on the signal or control circuit for the exhaust valve timing solenoid on Bank 2. In a functioning variable valve timing system, the ECM applies a precise pulse-width-modulated ground signal to the solenoid; the return voltage must stay within a calibrated window. A low-circuit condition — caused by a short to ground, an open in the power supply wire, or a solenoid with a broken internal winding — pulls the feedback signal below threshold, prompting the ECM to set P0085 and deactivate exhaust VVT on that bank. The exhaust cam phaser then defaults to its base position, which is often not optimal for the current operating condition. Symptoms include a rough idle, loss of torque at low-to-mid RPM, increased fuel consumption, and in severe cases, misfires. Because the low-voltage fault can also arise from water ingress into the connector or a damaged harness near the hot exhaust manifold, thermal inspection is an important diagnostic step alongside electrical resistance checks.
Common causes
Most-frequently reported root causes when P0085 is logged.
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1
Short-to-ground in the solenoid control wire causing a voltage drop below the ECM's low threshold
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2
Open circuit in the solenoid power supply wire — broken conductor or blown fuse — starving the circuit of voltage
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3
Faulty exhaust valve control solenoid with an open or partially broken internal coil winding
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4
Water or moisture ingress into the solenoid connector causing corrosion and increased resistance leading to low voltage
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5
Damaged wiring harness with conductors shorted to the chassis ground near exhaust heat sources
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6
Low or contaminated engine oil preventing adequate oil pressure to the solenoid and causing erratic electrical feedback
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7
Loose or corroded ground connection in the solenoid circuit reference path
Symptoms drivers notice
How to diagnose P0085
A typical diagnostic flow when this code is present.
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1
Scan for codes and freeze-frame data; note if P0084 or P0086 are also present to understand whether the fault is consistently low or intermittent
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2
Check and service engine oil if dirty or at low level before electrical diagnosis
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3
Inspect the Bank 2 exhaust solenoid connector and harness for moisture intrusion, heat damage from the exhaust manifold, or broken wires
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4
Measure voltage at the solenoid power supply pin with the ignition on — low or absent voltage suggests a blown fuse or broken supply wire
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5
Check for a short to ground on the control wire using a multimeter in continuity mode with the connector unplugged
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6
Measure solenoid coil resistance; an open reading (OL/infinite) confirms internal coil failure requiring solenoid replacement
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7
After repairs, clear codes and verify with live VVT cam-angle data during a test drive
Related powertrain codes
Frequently asked questions
Is P0085 a low-voltage or high-voltage fault?
P0085 is a low-voltage (or low-signal) fault. The ECM measured a voltage level below its calibrated minimum on the Bank 2 exhaust solenoid circuit. This is typically caused by a short to ground, an open power supply, or a failed solenoid coil.
Can I clear P0085 and keep driving?
Clearing the code is fine for diagnostic purposes, but if the fault condition remains the code will return. Driving with disabled exhaust VVT on Bank 2 causes reduced performance and fuel economy, and prolonged operation can accelerate phaser wear.
How do I tell apart a wiring fault from a bad solenoid for P0085?
Disconnect the solenoid connector and measure resistance at the solenoid terminals. If coil resistance is within spec (typically 6–12 Ω), the solenoid itself is likely good and the fault is in the wiring or connector. If resistance is open (OL) or far out of range, replace the solenoid.
Does P0085 affect Bank 1 or Bank 2?
P0085 specifically affects Bank 2, which is the engine bank that does not contain cylinder 1. The equivalent Bank 1 code is P0082 (intake low) or P0078 (exhaust low), depending on which cam is involved.
Disabling P0085 in software
RaceTune can permanently disable P0085 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.
Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.
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