CAN COMMUNICATION SYSTEM Certification ECU Communication Stop Mode

DTC Code	DTC Name
	Certification ECU Communication Stop Mode

DESCRIPTION


Detection Item	Symptoms	Trouble Area
Certification ECU Communication Stop Mode	Either condition is met: "Certification (Smart)" is not displayed on the "Bus Check" screen (Click here). Communication system DTCs (DTCs that start with U) that are output correspond to "Certification ECU Communication Stop Mode" in "DTC Combination Table" (Click here).	Certification ECU (smart key ECU assembly) CAN branch wire or connector Power source circuit of certification ECU (smart key ECU assembly) Certification ECU (smart key ECU assembly) ground circuit Certification ECU (smart key ECU assembly)

For vehicles with an entry and start system only.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

Note:

Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output (Click here).
Before measuring the resistance of the CAN bus, turn the ignition switch off and leave the vehicle for 1 minute or more without operating the key, switches or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.
After turning the ignition switch off, waiting time may be required before disconnecting the cable from the battery terminal. Therefore, make sure to read the disconnecting the cable from the battery terminal notice before proceeding with work (Click here).
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.
After the repair, perform CAN Bus Check and check that all the ECUs and sensors connected to the CAN communication system are displayed (Click here).
Before replacing the certification ECU (smart key ECU assembly), refer to the entry and start system (for Entry Function) (Click here).

Tip:

Operating the ignition switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.
Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the ECUs or wire harness while performing the inspection below may help determine the cause of the malfunction.

PROCEDURE

CHECK FOR OPEN IN CAN BUS WIRE (CERTIFICATION ECU CAN BRANCH WIRE)

Measure the resistance according to the value(s) in the table below.

Standard Resistance


Tester Connection	Condition	Specified Condition
H51-9 (CANH) - H51-10 (CANL)	Cable disconnected from negative (-) battery terminal	54 to 69 Ω

Table 1. Text in Illustration
*a	Rear view of wire harness connector (to Certification ECU [Smart Key ECU Assembly])

REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO CERTIFICATION ECU (CANH, CANL)

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - BATTERY AND BODY GROUND)

Connect the cable to the negative (-) battery terminal.

Note:
When disconnecting the cable, some systems need to be initialized after the cable is reconnected (Click here).

Measure the resistance according to the value(s) in the table below.

Standard Resistance


Tester Connection	Condition	Specified Condition
H51-15 (E) - Body ground	Always	Below 1 Ω

Measure the voltage according to the value(s) in the table below.

Standard Voltage

Table 2. Text in Illustration
*a	Rear view of wire harness connector (to Certification ECU [Smart Key ECU Assembly])

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

REPAIR OR REPLACE HARNESS OR CONNECTOR