The HECU interchanges requirement data with the 4WD ECU through CAN bus line for normal ABS control.
For example the HECU sends a control inhibition signal to 4WD ECU for normal ABS control in case of the ABS and 4WD control requested at the same time because wheel speed difference between front and rear wheel occurs.
The HECU checks absence of the 4WD message from the 4WD ECU for normal ABS control, and sets this code if an 4WD ECU message is not received within predefined time.
The HECU checks the presence and specific contents of the 4WD1 message from the 4WD ECU, and sets this code if there is an error in 4WD ECU message1.
Item
Detecting Condition
Possible Cause
DTC Strategy
CAN message monitoring
Faulty 4WD ECU
Faulty HECU
Monitoring Period
Continuous
Enable Conditions
Faults are detected if 4WD message was not received on time by the CAN controller of HECU
If the 4WD ECU detected an following error and informed the HECU about it via CAN, a fault is determined
- 4WD1 message timeout was detected by HECU
- 4WD1 data length code error was detected
- a failure of the 4WD ECU shift motor or encoder was detected
- a 4WD magnetic clutch failure was detected
- the 4WD ECU does not receive the TCS4 message any more
- the 4WD max cardan shaft torque contains faulty torque information
Fail-Safe
Inhibit the ABS/ESP control and allow the EBD control
ABS/ESP warning lamps are activated