Emissions - OBD Readiness Test Procedure
NUMBER: 11-72-04DATE: 08/04/04
APPLICABILITY:
All 1997 MY & Newer Subaru Vehicles
STATE I/M PROGRAM ADVISORY BULLETIN
SUBJECT:
On-Board Diagnostic System I/M
Check During State Emission Test
This bulletin provides advisory information.
About 30 states have implemented regulations for inspecting the vehicle's On-Board Diagnostic (OBD) system as part of their state emissions inspection program. EPA guidance permits up to two unset OBD system monitors as "Not Ready" and the OBD system testing will be considered valid for 1996-2000 model vehicles. No more than one unset readiness code monitor is allowed for 2001 and newer model vehicles. A state emission inspection may not pass a vehicle if the number of OBD system readiness monitors "Not Ready" or "Incomplete" is greater than stated above. Under this condition, the vehicle operator should be instructed to drive his/her vehicle for a few days to set the monitors before returning for an emission test re-inspection.
Summarized below is the recommended readiness code set procedure for 1997 and newer model Subaru vehicles. (In accordance with EPA guidance, 1996 model Subaru vehicles reset to "not ready" at key off, and they should never be rejected or failed based solely on readiness status. See bulletin 11-49-97K for further 1996 model details.)
1) Ensure the fuel level in the fuel tank is between 1/4 and 3/4 level. The recommended fuel level for this procedure is 1/2 fuel tank level.
2) Start the engine from cold condition and drive the vehicle for more than 15 minutes at a speed greater than 50 mph in order to ensure proper warm-up of the engine. Avoid sudden acceleration, hard braking, and sudden lane change during the warm up.
3) The vehicle should be driven at a steady-state speed of 55 mph with minimal throttle angle change for more than 3 minutes.
4) Verify the condition of readiness codes using a generic scan tool (GST).
Owners of rejected or failing vehicles may be instructed by the State I/M Program to contact their Subaru Dealer (and/or independent service provider) for service.
Please consult 2003 and later model Subaru Technical Service Manuals, or electronically by the Subaru Technical Information System (STIS) web site for more detailed drive cycle information.
The generic scan tool (GST) used for OBD I/M Check inspection by State I/M Program. Listed by model for 2004-2005 Subaru vehicles are the proper scan tool communication protocols. Earlier Subaru models use ISO 9141-2.
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