The ECM is connected to the CAN bus via the transfer case control module and controls differential operation using CAN·messages from other control units on the network. The main data transmitted to the control unit are: wheel speeds, steering angle, automatic transmission shaft speed, temperature information, vehicle configuration data, axle ratios and mode data.
The control unit also sends CAN·messages about the status of the electronically controlled rear differential to other control modules on the network. The main data transmitted by the control unit are: clutch torque and default mode status.
The following table shows the messages that may appear on the top row instrument cluster message center display and are related to the electronically controlled rear differential:
Message | Description | Sound alarm |
'TRANSMISSION OVERHEAT' 'SLOW DOWN' (transmission overheating, slow down) | The temperature of the rear differential has reached or is approaching the overheating threshold. | No |
'TRANSMISSION FAULT' 'TRACTION REDUCED' (transmission failure, tractive effort reduced) | The transfer case control module has stopped communicating on the CAN bus. Transition by default to an open type center differential. This message also appears if there is a malfunction in the electronically controlled rear differential. | No |
'TRANSMISSION FAULT' 'STOP SAFELY' (transmission malfunction, stop in a safe place) | There is a malfunction in the electronically controlled rear differential. Stop the vehicle as soon as possible. | Single beep |
On vehicles with a lower row instrument panel, a status lamp is used instead of the message center, which works according to the following principle:
- Yellow color - overheating
- Red color - malfunction, stop the car
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