An illuminated Check Engine Light could be caused by a defective VVT-i controller, which changes cam timing for optimal power. Updated parts are available and the repair may be covered under the powertrain warranty.
Scion tC Problem Reports
Most Reported Scion tC Problem Reports
Check Engine Light Illuminated
Problem: Diagnostic Showed Error Code 420: "Catalytic Converter Efficiency Below Threshold (Bank 1)
Solution: Free Replacement by Dealer Under California 7yr/70k or Federal 8yr/80k Warranty Covering Emissions Parts
Some vehicles may develop a condition where they cannot be shifted from "Park" to "Drive" and/or multiple warning lights illuminate when exposed to extreme cold conditions (-14 degrees F) or lower. Our technicians tell us the ignition (IG) relay should be replaced with an updated part to correct this concern.