Tech Tip: Subaru MIL Flashes with No Driveability Complaints – UnderhoodService

Tech Tip: Subaru MIL Flashes with No Driveability Complaints

You may encounter a Subaru on which the MIL flashes whenever the motor is running. There may not be any driveability complaints. The problem is that the green test mode connectors are hooked together. To diagnose the problem, locate the green single-wire test mode connectors under the driver's side of the dash by the steering column.

Vehicles affected: 1995-’99 Subaru Legacy 2.2L; 1996-2007 Subaru Legacy 2.5L; and 2002 Subaru Legacy 3.0L

Symptom: The MIL flashes whenever the motor is running. No driveability complaints. 

Problem: The green test mode connectors are hooked together.

Test & Fix: Locate the green single-wire test mode connectors under the driver’s side of the dash by the steering column. Under normal conditions the test mode connectors should not be connected. When the test mode connectors are connected together, the PCM goes into an active check mode. If it passes, the MIL will flash. When the test mode connectors are connected, the vehicle can also set false engine codes. Unplug the green test mode connectors to stop the check engine light from flashing.

Courtesy of Identifix, Inc.

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