# fmu----ecu----tcu???

**URL:** <https://forums.speedlife.net/t/fmu-ecu-tcu/81125>\
**Category:** SON240sx Automotive\
**Created:** [June 10, 2004, 11:51am UTC](https://forums.speedlife.net/t/fmu-ecu-tcu/81125 "2004-06-10T11:51:37Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![kellyanne](https://avatars.discourse-cdn.com/v4/letter/k/d78d45/32.png) [@kellyanne](https://forums.speedlife.net/u/kellyanne)\
**Post date:** [June 10, 2004, 11:51am UTC](https://forums.speedlife.net/t/fmu-ecu-tcu/81125/1 "2004-06-10T11:51:37Z")

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I would like to know what roles the:: FmU/ ECU/ TCU, cpiggy back chip, and feul pump(I thought there where 2 feul pumps) all play, I am very interested.

Stupid question???

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**Author:** ![Sven](https://avatars.discourse-cdn.com/v4/letter/s/e47c2d/32.png) [@Sven](https://forums.speedlife.net/u/Sven)\
**Post date:** [June 10, 2004, 3:11pm UTC](https://forums.speedlife.net/t/fmu-ecu-tcu/81125/2 "2004-06-10T15:11:53Z")

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ECU = brains of your car. Controls fuel maps, injector pulses, etc  
TCU = the little brain in the 240 that controls things like chimes, clock, and other various things.  
Piggy Back Chip = A form of ECU upgrade. Instead of replacing the ECU it sits between it and the ECU’s sensors and modifies the signal to achieve some result.  
Fuel Pump = Delivers fuel from the gas tank to the engine. Not that tricky. There is only 1 on our cars.

[www.howstuffworks.com](http://www.howstuffworks.com) has great stuff on all car subjects.