P0086
Exhaust Valve Control Solenoid Circuit High (Bank 2)P0086 is a generic OBD-II powertrain diagnostic trouble code: Exhaust Valve Control Solenoid Circuit High (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 P0086 means
P0086 is logged when the ECM detects an abnormally high voltage on the control circuit for the exhaust valve timing solenoid on Bank 2. In a healthy variable valve timing system the ECM modulates a ground-side driver to regulate solenoid duty cycle; if the feedback voltage rises above the calibrated upper limit — due to a short-to-power in the wiring, an internal solenoid winding fault, or an ECM driver issue — P0086 is set and exhaust VVT on Bank 2 is frozen at its default position. This directly impacts exhaust scavenging efficiency and can cause rough idle, loss of mid-range torque, and poorer fuel economy. A high-circuit fault often results from a chafed wire contacting a 12 V reference line, a solenoid connector that has bridged internally due to corrosion, or a voltage regulator drift. Because exhaust-side harnesses run close to heat sources, thermal degradation is a common root cause. The MIL illuminates immediately on the first confirmed detection; the ECM may store a freeze frame reflecting the conditions at fault onset.
Common causes
Most-frequently reported root causes when P0086 is logged.
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1
Short-to-power in the solenoid control wire routing it to a 12 V source instead of the ECM ground-side driver
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2
Internally shorted exhaust valve control solenoid coil drawing excessive voltage and feeding back above threshold
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3
Corroded connector bridging the control terminal to a supply pin, elevating circuit voltage
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4
ECM internal driver fault producing an elevated output on the Bank 2 exhaust solenoid channel
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5
Wiring harness chafed against the exhaust manifold or nearby heat source creating a short to the vehicle's power rail
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6
Faulty ECM voltage regulator supplying above-normal voltage to the solenoid circuit
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7
Previous improper wiring repair leaving a direct connection to battery positive
Symptoms drivers notice
How to diagnose P0086
A typical diagnostic flow when this code is present.
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1
Connect a scan tool, retrieve all stored codes, and note freeze-frame RPM and load data to identify the operating condition when the fault was first set
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2
Inspect the Bank 2 exhaust solenoid wiring harness, particularly near the exhaust manifold, for heat-damaged insulation or contact with a 12 V reference wire
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3
With the solenoid connector unplugged, measure voltage on the control wire — any significant positive voltage (approaching battery voltage) indicates a short-to-power that must be traced and repaired
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4
Measure solenoid coil resistance (spec typically 6–12 Ω); a near-zero reading indicates an internal short requiring solenoid replacement
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5
Inspect the ECM power supply voltage for over-voltage conditions that could affect multiple solenoid channels simultaneously
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6
Use scan tool live data to command the solenoid and monitor cam phaser response; compare Bank 2 exhaust timing to Bank 1 to isolate the fault
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7
After wiring repair or solenoid replacement, clear codes and verify with a road test monitoring exhaust cam-angle data
Related powertrain codes
Frequently asked questions
What distinguishes P0086 from P0084 and P0085?
P0084 is a general circuit malfunction on the Bank 2 exhaust solenoid without specifying direction. P0085 indicates a low-voltage fault (short to ground or open supply). P0086 indicates a high-voltage fault (short to power or over-voltage). Knowing the direction narrows diagnosis significantly.
Can P0086 damage the engine if not fixed?
Sustained incorrect exhaust cam timing increases combustion temperatures and can accelerate catalyst degradation. It also places the camshaft phaser in a position it was not designed to hold indefinitely, potentially causing premature phaser wear. Prompt repair is advised.
My scanner shows P0086 only after the engine warms up. Why?
Thermal expansion of wiring insulation near the exhaust manifold can intermittently expose a short-to-power contact only when hot. This heat-induced intermittent fault is a classic symptom of chafed harness insulation. Inspect the harness with the engine at operating temperature.
Should I replace the solenoid or repair the wiring first?
Always diagnose the circuit before replacing parts. Measure voltage on the control wire with the connector unplugged — if it shows battery voltage, the fault is in the wiring. If the wire tests normal and the solenoid coil reads near 0 Ω (internal short), then replace the solenoid.
Disabling P0086 in software
RaceTune can permanently disable P0086 — 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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