e4od in limp mode
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e4od in limp mode
Hello all I put a switch in my 97 f350 to manually unlock the torque converter and now the overdrive light flashes off. I heard this is called limp mode. Will this hurt my transmission? I know one thing it shifts firmer now. If I turn the switch to let the computer control the torque converter it still flashes. Will I need to get a code reader to clear out the codes? Is there any way to fool the computer to think it still has control even when I manually unlock it? Thanks in advance!
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Joined: Feb 2004
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From: North Bend Washington
The computer probably does not like the interuption. When you interupted the connection the computer thinks the converter clutch has failed "OFF". It may give you a code for a "TCC solenoid circuit failure" #629 for OBDI. For OBD II I do not know the code #.
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Joined: Sep 2006
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From: North Pole, Alaska
If you continue to drive with the transmission in "limp" mode the life of your tranny will be greatly shortened. Limp mode is a programmed feature that allows the transmission to operate with limited functionality in the event that there is a problem with the transmission controls, the limited functionality is accomplished by forcing the transmission control pressure as high as it can go which causes the transmission to delay upshifts and the shifts will be hard, basically the transmission will shift like you have the gas pedal floored all the time.
The reason your transmission is in limp mode is the TCC override switch you installed. When the PCM sends a signal to lock the TCC the PCM compares the engine RPM with the transmission output shaft RPM to verify that the TCC is locked, if the PCM senses slippage it throws a code for the TCC solenoid and the tranny goes into limp mode, the OD OFF light will blink constantly to inform you that it is in limp mode.
The reason your transmission is in limp mode is the TCC override switch you installed. When the PCM sends a signal to lock the TCC the PCM compares the engine RPM with the transmission output shaft RPM to verify that the TCC is locked, if the PCM senses slippage it throws a code for the TCC solenoid and the tranny goes into limp mode, the OD OFF light will blink constantly to inform you that it is in limp mode.
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Thanks for the replys. The only time it shifts hard is when the computer has control of the torque converter and the od light is flashing but when I manually disable it, it shifts firm and good. I'll try a programmer and see if it will let me adjust the shift points so it won't lockup so early.
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