I posted this question over at my old Cherokee Forum:
, I have a question I'm hoping you can answer. You were helpful with my Cherokee, and I appreciate it. I now have a 2017 New Compass Latitude with the C635 manual transaxle and Active Drive 4x4. With the Cherokee Active Drive I or higher systems, the PTU and RDM would engage automatically when certain conditions were met, such as outside temperature and wheel slippage. Now that it is getting colder out, it does not seem that my New Compass operates the same. When it is 20 F outside, the AD system is not engaged on its own. When I push the Lock button or place it in one of the three modes, it does engage. I can hear it, feel it, and notice a difference while driving. However, it does not seem to engage on its own. Is my perception correct? I did try it in snow in Auto, and it did provide instant grip. However, I did not feel it stay engaged all the time like the Cherokee KL did.
Thank you in advance for your assistance with my question. I am a curious owner .
New: 2017.5 Compass Latitude 4x4 6spd. Options: Cold Weather Group, Trailer Tow Group, Safety & Security Group, Popular Equipment Group, and Beats Premium Audio System.
Old: 2015 Trailhawk 3.2L, Nav, Tow, Cold Weather.
Trailer: Custom built Montrose aluminum 4.5'Wx6'Lx3'H off-road utility with 3,500 lb Dexter torsion axle. Known as the Zombie Escape Trailer.
Question for @JeepCares - 2014+ Jeep Cherokee Forums
Then another member posted this up for me:
Here's what I found in regards to your compass. I don't see anything about temperature in there so it may not operate the same way as the KL, although i would be very surprised, because even my Charger SXT AWD kicks into AWD under 40 degrees, just like the KL. but this may help, i'll keep digging to see if i can find something about temperature.
The Power Transfer Unit (PTU) engages and disengages the propeller shaft as requested by the Drivetrain Control Module (DTCM). The DTCM receives information from other modules via CAN line, such as the gear engaged, engine load, vehicle speed, the drive mode requested by the operator, etc., to determine when to engage or disengage the propeller shaft on the basis of the most appropriate strategy. The DTCM controls an actuator installed on the PTU to transmit torque to the propeller shaft.
In "Auto" mode, (DTCM) controls the Power Transfer Unit (PTU) actuator so that when starting from a standstill or speeds close to 0 km/h (0 mph) the propeller shaft is always engaged. When the vehicle speed exceeds a set threshold, the engine load is not too high and the road conditions are ideal, the DTCM will command the PTU actuator to disengage the propeller shaft for the purposes of saving fuel. The conditions for which the DTCM re-engages the propeller shaft are, for example:
If the road features irregular surfaces that compromises the dynamics/safety of the car.
If the car speed returns to close to 0 km/h (0 mph).
The propeller shaft is disengaged only if the Select Terrain selector is in AUTO mode and only at a specific speeds in order not to compromise driving safety.
In the case of system or selector faults, the mode change option will be automatically disabled. The system will automatically set itself to "Auto" mode. The DTCM has the capability of storing Diagnostic Trouble Codes (DTCs) that can be read using an appropriate diagnostic scan tool to aid in diagnosing the system.
The vehicle operator can select up to five operating strategies based on surface conditions.
AUTO (Automatic): the 4WD mode with continuous and automatic operation can be used while driving on road and off-road. This mode balances traction improving manoeuvring and acceleration when compared to a 2WD vehicle. This mode also reduces fuel consumption, since it disconnects the propeller shaft when 4WD is not necessary.
SNOW: this mode can achieve more stability on slippery or snow-covered grounds. To be used for driving on-road and off-road in the case of grounds with poor grip, such as roads covered by snow. In SNOW mode, depending on the operating conditions, the transmission may engage 2nd gear (rather than 1st) when setting off, in order to minimize wheel slipping.
SAND: off-road driving mode to be used on grounds with poor grip, such as sand. The transmission is boosted for maximum traction.
MUD : off-road driving mode for surfaces with poor grip, such as mud-covered grounds or wet grass.
ROCK: This mode is only available for vehicles equipped with the 4WD LOW range. Adjustment based on traction with boosted steering capacity, for use on off-road surfaces with good grip. This guarantees the best "off-road" performance. This mode is to be used for obstacles to tackle at low speed, such as large rocks, deep cracks, etc.
4WD LOCK (available with manual gearbox and automatic transmission): deactivates the function for disconnecting the propeller shaft, guaranteeing the immediate availability of the torque to the rear coupling. This function can be selected in AUTO mode and is automatic in the other driving modes.
4WD LOW (available for Trailhawk versions with automatic transmission): it enhances the "off-road" performance of the vehicle in all driving modes. Low range is achieved by launching the vehicle with 1st gear in the transmission, versus the normal operating strategy of launching in 2nd gear. The PTU is a single range unit, with no internal gear reduction.
Question for @JeepCares - 2014+ Jeep Cherokee Forums
Then Jeep posted this up for me:
This is directly from the Compass team:
"The Jeep Compass 4x4 comes standard with the Jeep Active Druve full time 4x4 system. The system features a fully disconnecting rear axle that disconnects at the Power Transfer Unit (PTU) and Rear Drive Module (RDM) reducing parasitic losses and maximizing fuel efficientcy, yet instantly engages when 4x4 traction is needed.
Jeep Active Drive:
• Intelligently selects FWD or 4WD (in Auto Mode) based on conditions and drive style
• Seamlessly engages 4WD providing confidence to drivers in all conditions
• Designed as a transparent system that requires no driver intervention or feedback in Auto Mode
• Power Take-Off Unit and Rear Differential Module have full disconnect to provide capability and fuel economy"
Jeep Social Care Specialist
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I learned a few things from this and thought I would share.