WARNING: Full-Time 4WD or AWD Subaru models must never be tested on a two-wheel dynamometer. Serious transmission damage could result.
Is it time to take your Subaru vehicle to your state emission inspection lanes or to visit a local authorized service station or independent repair shop for this service? If so, and you are the owner of a Full-Time 4-Wheel Drive (4WD) or All-Wheel Drive (AWD) Subaru model, this information is for you.
The 1990 Clean Air Act Amendments required the Environmental Protection Agency (EPA) to implement stricter vehicle emission control inspection programs to reduce air pollution from motor vehicles. Depending on the severity of a state's air pollution problems, states must adopt either a "basic" or "enhanced" vehicle emission test.
Typically, the basic test includes the insertion of an analyzer probe into the exhaust pipe of the vehicle during idle driving conditions for a short period. States with more severe air pollution problems (usually major metropolitan areas with populations of 200,000 or more) are required to perform the enhanced test. This test permits more accurate measurement of tailpipe emissions by simulating actual driving conditions on a dynamometer.
What is a Dynamometer?
A dynamometer is a treadmill or roller-like testing device that allows your car's wheels to turn while the car remains in one place. Some states have started using dynamometers in their state inspection programs in order to satisfy new federal laws calling for stricter emission standards for reduced air pollution. The problem? Dynamometers can be very damaging to the transmissions of Full-Time 4WD and AWD vehicles.
Some Subaru AWD owners have contacted Subaru of America, Inc. and their authorized Subaru dealers seeking warranty reimbursement for transmission damage caused by two-wheel dynamometer testing. These owners reported no driveability problems prior to state-enhanced emission testing, but sought repair for driveability symptoms (vibrations, noise on turns, etc.) within 100 miles after the improperly performed two-wheel dynamometer test. The Subaru Emissions Defect and Performance Warranties, which cover defects in your vehicle's materials and workmanship, do not cover damage resulting from improper testing.
States using a two-wheel dynamometer exempt Full-Time 4WD and AWD vehicles, including Subaru models, from dynamometer testing and perform only the basic two-speed idle tailpipe test. Four-wheel dynamometer testing is approved for Subaru Full-Time 4WD and AWD models. Avoid the aggravation and expense of post-emission testing repairs to your vehicle by following the recommendations below.
Don't Get Smoked!
- Contact your authorized Subaru dealer prior to state emission testing if you are unsure whether your vehicle has a Full-Time 4WD or AWD transmission.
- Alert your vehicle emission inspector prior to testing that your Subaru vehicle is either Full-Time 4WD or AWD-equipped and cannot be tested on a single two-wheel dynamometer.
- If your vehicle is improperly tested and exhibits driveability symptoms described above, we suggest you contact your authorized Subaru dealer or Subaru of America, Inc. immediately. All post-emission testing repairs should be performed at an authorized Subaru dealer to ensure that they are done properly.
- Contact Subaru of America, Inc. at 1-800-SUBARU3 if you have any additional questions.