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Service Questions
Why does my vehicle seem to perform differently when it's cold compared to when it warms up?
Toyota vehicles incorporate a sophisticated emissions system that works with the Engine Control Module (ECM) to warm the engine as quickly as possible by running it at high revolutions per minute (RPM) at idle, and by delaying upshifting on vehicles with an automatic transmission. Delaying upshifts keeps the cold engine's RPM higher while driving.
Emissions are highest when the engine is cold because the catalytic converter needs to be at a high operating temperature in order to function effectively. To get the engine and emissions system warmed as quickly as possible, the fast engine RPM at idle and delayed upshift continue until optimum operating temperature is reached.
Normal idle speed and automatic transmission shifting return when the engine and emissions systems are warmed to operating temperature.
Emissions are highest when the engine is cold because the catalytic converter needs to be at a high operating temperature in order to function effectively. To get the engine and emissions system warmed as quickly as possible, the fast engine RPM at idle and delayed upshift continue until optimum operating temperature is reached.
Normal idle speed and automatic transmission shifting return when the engine and emissions systems are warmed to operating temperature.