OBD-II code P0086 indicates the engine control module has detected a high voltage signal in the exhaust valve control solenoid circuit on Bank 2 (the cylinder bank that does not contain cylinder #1). This solenoid is part of the variable valve timing (VVT) system and uses oil pressure to adjust exhaust camshaft timing. A 'circuit high' condition typically points to an open circuit, a break in the wiring, or a disconnected/severely damaged solenoid.
The oil control valve solenoid itself is the most common failure point. Internal electrical failure, contaminated solenoid screens, or sticking valves are frequent root causes, especially in higher-mileage engines.
Corroded, chafed, broken, or unplugged wiring between the PCM and the Bank 2 exhaust VVT solenoid can produce a high-voltage/open-circuit reading. Heat and vibration near the exhaust side accelerate this damage.
VVT solenoids depend on clean oil at the correct pressure. Sludge, contamination, or oil that is long past its service interval can clog the solenoid screen and cause the circuit to read out of range.
Restricted oil flow to the exhaust camshaft phaser or actuator can trigger the code even when the solenoid and wiring are electrically sound.
A mechanically failed phaser can prevent the valve timing from moving as commanded, prompting the PCM to flag a circuit fault.
PCM failure is uncommon for this code and should only be considered after the solenoid, wiring, oil condition, and mechanical VVT components have all been ruled out.
Clearing the code only erases the stored fault. If the underlying mechanical or electrical problem is not repaired, the code will return, usually within a short drive cycle.
No. For P0086, the exhaust valve control solenoid itself or its wiring is the actual cause in the vast majority of cases. Replacing the PCM without first testing the solenoid, the connector, the wiring, and the engine oil condition is not an evidence-based repair and usually does not resolve the issue.
The vehicle will often still run, but you may notice rough idle, reduced power, and worse fuel economy. Extended driving with incorrect exhaust valve timing can increase wear on camshaft components and raise exhaust temperatures, so the fault should be repaired sooner rather than later.
No. P0086 is unrelated to the evaporative emissions or oxygen sensor systems. It specifically concerns the exhaust-side variable valve timing solenoid circuit on Bank 2, even though some of its symptoms (rough running, failed emissions test) can overlap with other faults.