The HECU send requirement data, such as Torque reduction, the number of fuel cut cylinders, and TCS control requests, to the Engine ECU ＆ TCU through CAN bus line. The Engine ECU performs fuel cut functions according to requests from the HECU and retards ignition timing by torque reduction requests. The TCU maintains current gear positions during TCS control time, in order not to increase power which causes a Kickdown shift.
The HECU checks the CAN communcation lines for normal ESP control, and sets this code if an CAN message is not transmitted within predefined time.
Item | Detecting Condition | Possible cause |
DTC Strategy | ● CAN massage monitoring | ● Faulty HECU |
Monitoring Period | ● Continuous | |
Enable Conditions | ● Faults are detected if CAN message was not transmitted on time by the CAN controller of HECU. | |
Fail Safe | ● Inhibit the ESP control and allow the ABS/EBD control. Meanwhile, stop checking the ESP switch failure under the ESP control. |
Ignition "OFF".
Engine "ON".
Does warning lamp remain On?
▶ Substitute with a known-good HECU and check for proper operation. If problem is corrected, replace HECU and then go to "Verification of Vehicle Repair" procedure.
▶ Fault is intermittent caused by faulty HECU or was repaired and HECU memory was not cleared. Go to the applicable troubleshooting procedure.
After a repair, it is essential to verify that the fault has been corrected.
Connect scantool and select "Diagnostic Trouble Codes(DTCs)" mode
Using a scantool, Clear DTC.
Operate the vehicle within DTC Detecting Condition in General Information.
Are any DTCs present ?
▶ Go to the applicable troubleshooting procedure.
▶ System performing to specification at this time.
