Start by checking the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.
The cost to diagnose the P1087 SUBARU code is 1.0 hour of labor. The auto repair's diagnosis time and labor rates vary by location, vehicle's make and model, and even your engine type. Most auto repair shops charge between $75 and $150 per hour.
The tumble generator system uses an electronically controlled butterfly valve in each intake runner port. At cold idle, the tumble generator system will redirect the air charge through a different port. These ports have a finish characteristic that causes the air/fuel mixture to swirl and tumble greatly and create better combustion. This results in greater idle quality, cleaner emissions, and easier cold-starts.
Once the vehicle warms up, the tumble generator system will be deactivated and the intake air charge will be directed through the standard intake ports.
The tumble generator sensor is responsible for measuring the position of the tumble generator butterfly valves. As the butterfly valves are opened or closed, signal voltage will vary accordingly at the position sensor.
The Diagnostic Trouble Code (DTC) will set when the ECM detects a high voltage signal from the tumble generator valve position sensor.
Need more information on how to fix the P1087 SUBARU code?
Get Access to Factory Service Manuals
Get the P1087 Subaru code diagnosed by a professional: Find a repair shop in your area