# 1999 ford ranger 3.0 engine Check engine light code 1504

**URL:** <https://community.cartalk.com/t/1999-ford-ranger-3-0-engine-check-engine-light-code-1504/31761>\
**Category:** Maintenance/Repairs\
**Created:** [June 11, 2009, 11:01pm UTC](https://community.cartalk.com/t/1999-ford-ranger-3-0-engine-check-engine-light-code-1504/31761 "2009-06-11T23:01:57Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![malibu1966](https://avatars.discourse-cdn.com/v4/letter/m/54ee81/32.png) [@malibu1966](https://community.cartalk.com/u/malibu1966)\
**Post date:** [June 11, 2009, 11:01pm UTC](https://community.cartalk.com/t/1999-ford-ranger-3-0-engine-check-engine-light-code-1504/31761/1 "2009-06-11T23:01:57Z")

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auxillary idle speed control. What is the most likely part replacement require?

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**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\
**Post date:** [June 11, 2009, 11:26pm UTC](https://community.cartalk.com/t/1999-ford-ranger-3-0-engine-check-engine-light-code-1504/31761/2 "2009-06-11T23:26:19Z")

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This code usually points to a short within the Idle Air Control motor. This can be a short to power or a short to ground. This code can also be caused from a short to and from the IAC motor, or form a bad ECU. But 99.99% of the time, it’s because of a defective IAC motor.

Tester