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.
Car Problem Reports
Scion tC Check Engine Light Due to Defective VVT-i Controller
Scion tC Problem
Average Mileage: 82,783 mi (32,000 mi - 133,567 mi)
Rough idle, high acceleration noise. Need to repair, just happened.
Visitor, 2005 Scion tC, 32,000 mi
dash lights have been on for quite some time. Had a mechanic look at it and was told the camshaft gear assembly needs to be replaced at about $700.00.