CAN COMMUNICATION SYSTEM Engine Stop and Start ECU Communication Stop Mode

DTC Code	DTC Name
	Engine Stop and Start ECU Communication Stop Mode

DESCRIPTION


Detection Item	Symptom	Trouble Area
Engine Stop and Start ECU Communication Stop Mode	Either condition is met: "Stop and Go/Start" is not displayed on the "CAN Bus Check" screen (Click here). Communication system DTCs (DTCs that start with U) that are output correspond to "Engine Stop and Start ECU Communication Stop Mode" in "DTC Combination Table" (Click here).	Engine stop and start ECU CAN branch wire or connector Power source circuit of engine stop and start ECU Engine stop and start ECU ground circuit Engine stop and start ECU

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).

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 (ENGINE STOP AND START ECU CAN BRANCH WIRE)

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

Standard Resistance


Tester Connection	Condition	Specified Condition
H121-15 (CANH) - H121-16 (CANL)	Cable disconnected from negative (-) battery terminal	54 to 69 Ω

Table 1. Text in Illustration
*a	Rear view of wire harness connector (to Engine Stop and Start ECU)

REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO ENGINE STOP AND START ECU (CANH, CANL)

CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START 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).
Disconnect the engine stop and start ECU connector.

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

Standard Resistance


Tester Connection	Condition	Specified Condition
A73-8 (GND) - 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 Engine Stop and Start ECU)

REPLACE ENGINE STOP AND START ECU

REPAIR OR REPLACE HARNESS OR CONNECTOR