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I drive a Lexus HS250h. It's starting to get very cold here and after the car has been parked outside all day, the HSD system acts differently. Normally, when the coolant reaches 139deg, the ICE shuts down when you lift off the gas pedal. Additionally, when the coolant gets to 157deg, it will transition from Stage 3 to Stage 4 when you stop for 10 seconds. The past few days I haven't been able to get the ICE to shut down when I lift off the gas and couldn't get it to transition from S3 to S4 until the coolant temp is approx 188-190. Ambient temp is something like 25deg or lower when this happens. Has anybody experienced anything like this with their HSD system (HS250h, Prius or TCH)?

If climate control demands heat (which comes from engine coolant) the engine will often run when you would expect it to shut down. I don't often bother with cabin heat on my short-ish commute but I do see this behavior when I run the defroster.

If climate control demands heat (which comes from engine coolant) the engine will often run when you would expect it to shut down. I don't often bother with cabin heat on my short-ish commute but I do see this behavior when I run the defroster.

I didn't use the heater or defroster in any of those situations.