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2001 Lexus RX 300 Base 4dr SUV

2001 Lexus RX 300
Trim Info:
Front Wheel Drive, 4 Door SUV, Mid-Size Station Wgn
19 mpg city / 23 mpg hwy
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March 25, 2013, 2:08 pm

Kunle A

Question: please list the functions of the electronic control unit or the brain box

ECU Module or brainbox functions

April 1, 2013, 10:50 am

Ron W
Expert Mechanic

Your vehicle has several "brain boxes". the ECU (as termed by Lexus) controls the power train which includes fuel strategies, emission reduction components, and possibly the transmission shifting patterns.

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April 1, 2013, 2:33 pm

Kunle A

What Is "Stuck blend door" ?

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April 1, 2013, 2:34 pm

Kunle A

also, what do u mean by "fuel strategies" ?

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April 1, 2013, 4:46 pm

Ron W
Expert Mechanic

A blend door is a mechanical door that controls temperature in the passenger compartment by direction air across the AC evaporator or the heater core. By changing direction you end up with either hot , cold, or warm air. Sometimes they get stuck in one position so you end up with that temp air, no matter what your AC or heater is doing.

Fuel strategies are basically what the computer decides the correct air/fuel ratio for any particular engine load is. When you accelerate, it will richen the mixture as opposed to when you decelerate when it leans out the mixture. It's based on engine load, driver demand, coolant temperature, as well as other senor inputs sent to the ECM. In short, its how much fuel the computer thinks you need (and hopefully get) when you are doing different things with your car.

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