Can you operate 1999 Jeep Cherokee sports auto trans with the TCU disconected ?
Will only run 40mph
Your transmission could be stuck in limp mode. This is very common. Anything from a transmission internal malfunction to a bad speed sensor can cause the computer to put the transmission in limp mode. Chances are there are trouble codes in the computer that will point you in the right direction. Your local auto parts store will do this for free for you.
If there is a fault detected with the accelerator pedal position sensor, the PCM will set the engine speed at 1100 RPM.
There are four preprogrammed modes from which the GPEC1 bases initial valve timing.
- Idle or Part throttle
- Wide open throttle
- Limp-in or Default
From each preprogrammed mode, the GPEC1 adjusts valve timing based on operating conditions.
GPEC1 has calculated optimum intake valve timing of 112 degrees after Top Dead Center and optimum exhaust valve timing of 97 degrees before Top Dead Center. The GPEC1 pulse width modulates the oil control valves to advance or retard the camshaft to their desired location. The spool valve inside the intake oil control valve is energized and moves to allow pressurized oil into the advance chambers of the intake cam phaser. At the same time, the spool valve inside the exhaust oil control valve is energized and moves to allow pressurized oil into the retard chambers of the exhaust cam phaser. Oil enters the advance chambers of the intake phaser and the retard chambers of the exhaust phaser. Oil pressure releases the lock pin from its locked position and pushes against the rotor vane. Both the rotor vanes are moved, advancing the intake camshaft and retarding the exhaust camshaft.