Durango 2WD V8-5.7L Hybrid (2009)
Overdrive Switch: Description and Operation
Overdrive Lockout Switch - Operation
OPERATION
Tow/haul is only used in the D position. When used while towing, the electronic control module (ECU) commands hybrid system to create more positive
axle torque to the wheels. When used while coasting downhill and the vehicle gains speed, the ECU commands the hybrid system to create more negative
axle torque to the wheels, helping the vehicle to maintain the correct speed.
The Powertrain Control Module (PCM) stores a target speed when the accelerator and brake are released, if vehicle speed increases due to a hill, then
additional negative wheel torque is added to the PCMs wheel torque request.
The Hybrid Control Processor (HCP) follows the PCMs command and downshifts as required to meet the negative torque request.
