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What is the 'power' light meaning?


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When it comes on when you mash the throttle, it means the transmission is in "Power" mode, which changes the shift points and boosts the pressure in the transmission to make it shift faster.

If it flashes, it means that there is a fault, there is an article in the USRM on 4EAT code retreival.

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EndWrench.com has good articles on the 4EAT:

 

Some models have a POWER light located to the left of the tachometer (right on Legacy). It is activated momentarily whenever the vehicle is started. The POWER mode is selected by the computer based upon how quickly the gas pedal is depressed. This changes the performance characteristics of the transmission. i.e., it delays upshifts and may downshift if necessary. When selected, the computer turns the POWER light “ON.”

 

ATF Temperature Sensor When the ATF is hot (AWD only), the TCU shifts the transmission as if in the POWER mode. This pushes the shift points higher which allows the engine to run faster. The oil pump then circulates ATF through the oil cooler more quickly so as not to overheat the engine coolant.

 

Power Indicator Light The POWER Indicator Light is located in the combination meter. It is activated momentarily whenever the vehicle is started as part of the self check system. It turns “ON” when the TCU selects the POWER mode with the vehicle in the “D” range. It blinks a self diagnostic code whenever the TCU is programmed for self diagnosis.

 

The TCU monitors the throttle angle opening speed, i.e., how quickly the gas pedal is depressed. When a predetermined rate is exceeded, the POWER mode is activated.

NOTE: THERE ARE A NUMBER OF PREDETERMINED RATES BASED ON THE VEHICLE SPEED VS. THROTTLE ANGLE RELATIONSHIP. THESE DETERMINE EASE OF ACCESS TO POWER MODE. AS A GENERAL RULE, IT IS EASIER TO ACTIVATE THE POWER MODE AT LOWER SPEEDS FROM A LIGHT THROTTLE

THAN IT IS AT HIGHER SPEEDS FROM A LIGHT THROTTLE.

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EndWrench.com has good articles on the 4EAT:

 

ATF Temperature Sensor When the ATF is hot (AWD only), the TCU shifts the transmission as if in the POWER mode. This pushes the shift points higher which allows the engine to run faster. The oil pump then circulates ATF through the oil cooler more quickly so as not to overheat the engine coolant.

 

is this related with 'AT oil temp' light in the meter panel? On my `91 2wd legacy it does not go on when i start. The 'power' and 'economy' lights come on normally. Is there something wrong with the ATF light??

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