# Check engine light on

**URL:** <https://community.cartalk.com/t/check-engine-light-on/35688>\
**Category:** Maintenance/Repairs\
**Tags:** rainier, buick\
**Created:** [August 28, 2009, 2:14am UTC](https://community.cartalk.com/t/check-engine-light-on/35688 "2009-08-28T02:14:04Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![needmechanic](https://avatars.discourse-cdn.com/v4/letter/n/67e7ee/32.png) [@needmechanic](https://community.cartalk.com/u/needmechanic)\
**Post date:** [August 28, 2009, 2:14am UTC](https://community.cartalk.com/t/check-engine-light-on/35688/1 "2009-08-28T02:14:04Z")

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'04 Buick Rainier. Friend’s diagnostic tool identifies problem as “engine coolant temperature circuit - high input”. What does this mean? Advice appreciated.

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**Author:** ![hellokit](https://avatars.discourse-cdn.com/v4/letter/h/6a8cbe/32.png) [@hellokit](https://community.cartalk.com/u/hellokit)\
**Post date:** [August 28, 2009, 7:23am UTC](https://community.cartalk.com/t/check-engine-light-on/35688/2 "2009-08-28T07:23:10Z")

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It means that the voltage the engine computer (ECM) expects to see (between 0 and 5 volts) isn’t what it should be. There may be a short in the wiring or in the engine coolant temperature sensor (ects). The repair manual will show you how to check the ects and its wiring.

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**Author:** ![needmechanic](https://avatars.discourse-cdn.com/v4/letter/n/67e7ee/32.png) [@needmechanic](https://community.cartalk.com/u/needmechanic)\
**Post date:** [August 28, 2009, 1:34pm UTC](https://community.cartalk.com/t/check-engine-light-on/35688/3 "2009-08-28T13:34:41Z")

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I’ll check it out. Other comments/advice still appreciated in case this doesn’t lead to a solution. Thanks!