Scion hard start after power interruption
This TSB applies to all Scion models equipped with electronic throttle control (ETCS). The engine may be difficult to start, or may feature an abnormally low or rough idle after the battery has been disconnected or power to the engine ECM has been interrupted.
Inspect the throttle body for excessive deposits. Clean the deposits using a rag that has been sprayed with throttle plate cleaner (Do not spray cleaning chemicals directly into the throttle body. The solution can carry contamination through the throttle shaft and damage the throttle motor or position sensor).
Once the cleaning is complete, allow the engine to idle for at least three minutes after the engine reaches full operating temperature.