Dodge Caliber. Manual

MODULE - FINAL DRIVE CONTROL

DESCRIPTION

The ECC is controlled by it’s own controller that is located in the left kick panel area. It gets signals over the CAN
bus from the ABS Wheel speed sensors and TPS signal.

OPERATION

The all-wheel-drive system requires no driver input or control. Under most driving conditions, it is passive and power
is transmitted to the front wheels alone. Unlike all-wheel drive systems that rely on pumps or viscous fluids to trans-
fer torque, this system requires no front-to-rear slippage for activation. This allows the system to transfer torque
solely in response to accelerator pedal position. If the driver is asking for a lot of power, the system immediately
starts clamping the electronically controlled coupling (ECC), transferring a high percentage of power to the rear
wheels. This avoids front wheel slippage, as power to propel the car is transmitted through all four tires. This mode
of operation is called open-loop operation in that there is no feedback to affect the torque transfer.

A second, closed loop, operating mode uses feedback from the wheel-speed sensors to determine the appropriate
torque transfer. When the front wheels slip, the allwheel- drive electronic control module tells the ECC to start
clamping, sending power to the rear wheels. Attempting the same aggressive launch described above with the front
wheels on ice and the rear wheels on dry pavement, the ECC sends even more torque to the rear wheels to min-
imize slippage and launch the vehicle. Both modes are always active with the closed loop mode layered on top of
open loop mode to increase torque to the rear wheels when needed to maintain traction in extreme cases.

Power to the rear wheels is modulated under the following conditions:

•

Slipping on ice while backing up will send

a lot of power to the rear axle

•

Loss of traction while traveling at freeway speeds, for example hydroplaning on a

puddle of water, will send very little power to the rear wheels because the controller knows at those speeds a lot of
power is not needed at the rear wheels A third condition, which is independent of the others, uses wheel speed
differences to determine when the vehicle is turning in a tight circle. This condition, which is indicated by a large
discrepancy in side-to-side wheel speeds, causes the electronic control module to reduce torque to the rear wheels
to prevent binding in the driveline. The electronic control module is always checking for this condition as well. A
fourth condition that is unique to the Caliber system is to influence vehicle dynamics. Other manufacturers limit AWD
to aiding traction or providing off-road capability. They concentrate on launching the vehicle or going off road at
speeds up to about 25 mph (40 km/hr). Above that speed range, they use it to limit wheel slip for traction. On this
system, additional ECM calibration controls torque to the rear wheels for improved handling in the 25-65 mph (40-
105 km/hr) range. In this speed range, the system increases torque to the rear wheels during cornering with the
throttle open to make the car turn more easily – make the handling more neutral. This is more readily accomplished
with an electronically controlled system, than with viscous-coupling or gerotor systems that require some degree of
front-to-rear slip to transfer torque to the rear wheels. Above 70 mph (113 km/hr), the control strategy provides
minimal torque to the rear wheels under normal driving conditions to aid fuel economy. The ECC system is easier
to calibrate, more flexible and more precise than viscouscoupling, Torsen

, or gerotor system, but less costly. It is

also less costly than the systems used in luxury cars from other manufacturers while providing similar functionality.
The electronic control module also interfaces with the ESP and traction control systems. The interface allows the
ESP system to use the ECC to help gain control of the vehicle. For this purpose, torque transmitted to the rear
wheels by the ECC can be reduced. The Caliber AWD system is not traction control. It only works on situations
where front-to-rear traction varies, for instance, front wheels on ice, rear wheels on dry pavement or climbing steep
grades. AWD does not aid side-to-side traction. ESP does that through brake intervention on this system.

8E - 204

ELECTRONIC CONTROL MODULES - SERVICE INFORMATION

REMOVAL

1. Remove the left front kick panel (Refer to 23 -

BODY/INTERIOR/COWL TRIM - REMOVAL).

2. Remove module retaining bolts (2).

3. Remove electrical connector (3).

4. Remove ECC module (1).

INSTALLATION

1. Plug ECC module in (3).

2. Move into place, install bolts (2) and torque to 11

N·m (97 in. lbs.).

3. Install the left front kick panel (Refer to 23 - BODY/

INTERIOR/COWL TRIM - INSTALLATION).

ELECTRONIC CONTROL MODULES - SERVICE INFORMATION

8E - 205

Dodge Caliber. Manual - part 273