Operation CHARM: Car repair manuals for everyone.
Home >> Jeep >> 1993 >> Cherokee 4WD L4-150 2.5L VIN P MFI >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Shift Light >> Description and Operation
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Shift Light: Description and Operation

PURPOSE
This light is only used in vehicles equipped with a manual transmission. It is illuminated to indicate that the driver should shift to the next higher gear for best fuel economy.

OPERATION
This light is illuminated when the ignition switch is turned to the ON position and should go OFF after the engine has started. Engine speed and load are what determines when the Powertrain Control Module (PCM) turns the light on.

The PCM will illuminate to indicate that the driver should shift to the next higher gear for best fuel economy.

The PCM will turn this light OFF if the up-shift hasn't occurred within 3 to 5 seconds of its initial illumination. The light will come back ON if acceleration has stopped and the engine RPM has dropped below the range of shift light operation.


NOTE: Once the vehicle has been shifted to its highest gear the light will not illuminate, due to the operation of a switch located on the transmission.
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