CAN COMMUNICATION SYSTEM(w/ Central Gateway ECU) DIAGNOSIS SYSTEM

CHECK FOR INSTALLED SYSTEMS (ECUS AND SENSORS) THAT USE CAN COMMUNICATION

The systems (ECUs and sensors) that use CAN communication vary depending on the vehicle and optional equipment. Check which systems (ECUs and sensors) are installed to the vehicle.

Bus	Code	ECU/Sensor Name	GTS Display	Applicability
-	CGW	Central gateway ECU (network gateway ECU)	CAN Gateway1 CAN Gateway2	Installed on all vehicles
V bus	DLC3	DLC3	-	Installed on all vehicles
Bus 2	ENG	ECM	ECM (Engine)	Installed on all vehicles
	BRK	Brake booster with master cylinder assembly (skid control ECU)	Skid Control (ABS/VSC/TRAC)	Installed on all vehicles
	MB	Main body ECU (multiplex network body ECU)	Main Body	Installed on all vehicles
	A/C	Air conditioning amplifier assembly	Air Conditioning Amplifier	Installed on all vehicles
	EPS	Power steering ECU assembly	Power Steering (EPS)	Installed on all vehicles
	SMT	Certification ECU (smart key ECU assembly)	Certification (Smart)	Installed on all vehicles
	STR	Spiral cable with sensor subassembly (steering angle sensor)	Spiral cable (Steering Angle Sensor)	Installed on all vehicles
	SRS	Airbag sensor assembly	Airbag	Installed on all vehicles
	PCN	Transmission control ECU assembly	Transmission Control	Installed on all vehicles
	MET	Combination meter subassembly	Combination Meter	Installed on all vehicles
	HV	Hybrid vehicle control ECU	Hybrid Vehicle Control	Installed on all vehicles
Bus 3	AV	Navigation receiver assembly	Display and Navigation (AVN)	Vehicles with Navigation Receiver Type
Bus 3	AV	Radio and display receiver assembly	Display and Navigation (AVN)	Vehicles with Radio and Display Type
Bus 5	HV	Hybrid vehicle control ECU	Hybrid Vehicle Control	Installed on all vehicles
	PAC	Parking assist ECU	Parking Assist (Intelligent Parking Assist)	Vehicles with Intelligent Parking Assist System
	DS	Driving support ECU assembly	Driving Support (Cruise Control-ACC)	Vehicles with Pre-crash Safety System
	F-CAM	Lane departure warning camera	Front Camera Module	Vehicles with Lane Departure Alert System
Sub bus 13	DS	Driving support ECU assembly	Driving Support (Cruise Control-ACC)	Vehicles with Pre-crash Safety System
Sub bus 13	F-MR	Millimeter wave radar sensor assembly	-	Vehicles with Pre-crash Safety System
Sub bus 15	HV	Hybrid vehicle control ECU	Hybrid Vehicle Control	Installed on all vehicles
	ENG	ECM	ECM (Engine)	Installed on all vehicles
	BRK	Brake booster with master cylinder assembly (skid control ECU)	Skid Control (ABS/VSC/TRAC)	Installed on all vehicles

Tech Tips

The names of ECUs and sensors shown on the GTS display may differ from those shown in the DTC Table by ECU section.

CAN BUS CHECK

Tech Tips

The ECUs and sensors that are properly connected to the CAN communication system can be displayed using the GTS.

Using the GTS, select the CAN Bus Check screen.

Note

It may be possible to select buses that do not have ECUs or sensors from the bus selection pull-down menu. This is not a malfunction. (This occurs when optional devices are not on a sub bus that is monitored by a gateway function equipped ECU.)
In the bus selection pull down menu, all buses applicable to the model are displayed (e.g. LIN communication buses are also displayed). Therefore, refer to the wiring diagrams to check the names of sub buses for CAN communication Click here.

Tech Tips

Different connection statuses are indicated by the background color of ECUs and sensors that are displayed.

Explanation of CAN Bus Check Screen
Bus Type	Background Color	Connection Status
Bus 2	White	Communication has been normal since the start of the CAN bus check.
	Yellow	Communication stop occurred at least once since the start of the CAN bus check, but communication is currently occurring (unstable communication).
	Red	Communication was established at least once since the start of the CAN bus check, but communication is currently not occurring (unstable communication).
	Not displayed	Communication stop has continued since the start of the CAN bus check.*1
Non-bus 2 (gateway function equipped ECU that does not have history of connected ECUs)*2	White	Communication has been normal since the start of the CAN bus check.
	Yellow	Communication stop occurred at least once since the start of the CAN bus check, but communication is currently occurring (unstable communication).
	Red	Communication was established at least once since the start of the CAN bus check, but communication is currently not occurring (unstable communication).
	Not displayed	Communication stop has continued since the start of the CAN bus check.*1
Non-bus 2 (gateway function equipped ECU that has history of connected ECUs)*3	White	Communication has been normal since the start of the CAN bus check.
	Yellow	Communication stop occurred at least once since the start of the CAN bus check, but communication is currently occurring (unstable communication).
	Red	Currently not communicating (either of the following): Communication stop has continued since the start of the CAN bus check. Communication was established at least once since the start of the CAN bus check, but communication is currently not occurring.
	Not displayed	Either of the following: If a gateway function equipped ECU cannot communicate, the non-bus 2 and ECUs connected to the non-bus 2 will not be displayed. If no ECUs are connected to the non-bus 2, "There is no system found on the Communication Bus" will be displayed.

Tech Tips

Gateway function equipped ECUs relay signals between the ECUs connected to the different buses.
*1: ECUs that are present in the vehicle but are not displayed on the CAN Bus Check screen.
*2: Gateway function equipped ECU that does not memorize the non-bus 2 ECUs that are connected to it.
*3: Gateway function equipped ECU that memorizes the non-bus 2 ECUs that are connected to it.
If none of the connected ECUs are displayed, or there is no response from the vehicle to the GTS, check the central gateway ECU and the V bus main bus lines for a malfunction.

Observe the connection response screen for approximately 2 minutes to check for a change in connection status of the connected ECUs and sensors.
Tech Tips
- If an open occurs in one of the lines of a CAN branch (except DLC3), output from the other branch line (the line that is not open) will be unstable and it may interfere with the response (display) of other ECUs and sensors.
- If the connection status changes during the inspection, repair the open in the branch line of the ECU or sensor that does not respond (is not detected) and then perform the CAN bus check again.

HOW TO INTERPRET CAN BUS CHECK SCREEN

When a communication stop is currently occurring, the probable malfunctioning part can be determined from the CAN bus check and by using the following methods.

Note

The following CAN bus wiring diagram is provided only as an example. This wiring diagram is different from the actual wiring diagram for this vehicle.
Tech Tips
- When a communication stop is currently occurring, it is easier to determine the probable malfunctioning part from the CAN bus check rather than from communication DTCs.
- Wait for approximately 2 minutes after turning the power switch on (IG) (or simulate the driving conditions that enable the malfunction to be reproduced) and select "CAN Bus Check". Then observe the communication status of each ECU on the screen.

If a communication error of only 1 ECU or sensor is indicated on the CAN Bus Check screen, a communication stop of the ECU or sensor is suspected.

Example: Open in both CAN branch lines of ECU D on the bus 2

Text in Illustration
*a	Bus 2	*b	Non-bus 2
*c	V Bus	*d	Terminating Resistor
*e	Location of Malfunction	*f	Not displayed or background color changes to red or yellow
*g	CAN Bus Check Screen	*h	Central Gateway ECU (Network Gateway ECU)

Tech Tips

When there are communication stops, ECUs that are present in the vehicle may not be displayed on the CAN Bus Check screen.

Text in Illustration
*a	Background color periodically changes to yellow or red
*b	Not displayed or background color is yellow or red
*c	Not displayed

If communication errors for multiple ECUs or sensors are indicated on the CAN Bus Check screen, then a communication stop of the ECU or sensor that shows a more serious communication stop (an ECU or sensor which is not displayed) is suspected.

Example: Open in a CAN branch line for ECU B on the bus 2

Explanation of CAN Bus Check Screen
Bus Type	Background Color	Connection Status
Bus 2	White	Communication has been normal since the start of the CAN bus check.
	Yellow	Communication stop occurred at least once since the start of the CAN bus check, but communication is currently occurring (unstable communication).
	Red	Communication was established at least once since the start of the CAN bus check, but communication is currently not occurring (unstable communication).
	Not displayed	Communication stop has continued since the start of the CAN bus check.*1
Non-bus 2 (gateway function equipped ECU that does not have history of connected ECUs)*2	White	Communication has been normal since the start of the CAN bus check.
	Yellow	Communication stop occurred at least once since the start of the CAN bus check, but communication is currently occurring (unstable communication).
	Red	Communication was established at least once since the start of the CAN bus check, but communication is currently not occurring (unstable communication).
	Not displayed	Communication stop has continued since the start of the CAN bus check.*1
Non-bus 2 (gateway function equipped ECU that has history of connected ECUs)*3	White	Communication has been normal since the start of the CAN bus check.
	Yellow	Communication stop occurred at least once since the start of the CAN bus check, but communication is currently occurring (unstable communication).
	Red	Currently not communicating (either of the following): Communication stop has continued since the start of the CAN bus check. Communication was established at least once since the start of the CAN bus check, but communication is currently not occurring.
	Not displayed	Either of the following: If a gateway function equipped ECU cannot communicate, the non-bus 2 and ECUs connected to the non-bus 2 will not be displayed. If no ECUs are connected to the non-bus 2, "There is no system found on the Communication Bus" will be displayed.

Tech Tips

Gateway function equipped ECUs relay signals between the ECUs connected to the different buses.
*1: ECUs that are present in the vehicle but are not displayed on the CAN Bus Check screen.
*2: Gateway function equipped ECU that does not memorize the non-bus 2 ECUs that are connected to it.
*3: Gateway function equipped ECU that memorizes the non-bus 2 ECUs that are connected to it.
The example of the CAN Bus Check screen in the illustration shows the result of electrical noise on the CAN bus which is caused by an open in a CAN branch line of ECU B (output from the other branch line is unstable) and the communication of ECU A is also unstable. In addition, in this example, ECU A is equipped with a gateway function. Therefore, communication is also unstable between the non-bus 2 ECUs of ECU A and the bus 2.
The example in the illustration shows that ECU B is not displayed on the CAN Bus Check screen. This indicates a more significant communication stop. In this case, a communication stop of ECU B is suspected.

Text in Illustration

*a Not displayed or background color changes to red

If a communication error is indicated on both the bus 2 and non-bus 2 on the CAN Bus Check screen, suspect any communication stop displayed for the bus 2 first.

Example: Open in both CAN branch lines of ECU A on the bus 2
Tech Tips
- In the CAN bus check, it is possible to confirm the communication status of ECUs connected to the bus 2 after connecting the GTS to the DLC3. As for non-bus 2, it is possible to confirm which non-bus 2 connected ECUs can communicate with a gateway function equipped ECU on the bus 2.
- If a gateway function equipped ECU has a communication error, ECUs connected to the gateway function equipped ECU are also affected, and communication stops will be indicated.
- The CAN Bus Check screen in the illustration shows that ECU A has a gateway function and a communication stop in ECU A is suspected.
Text in Illustration

*a Background color changes to red

If the CAN Bus Check screen indicates a communication stop only in the non-bus 2, a communication stop in the non-bus 2 is suspected.

Example: Open in both CAN branch lines of ECU G on the non-bus 2
Tech Tips
- A communication error in a non-bus 2 does not affect the bus 2 or other buses.
- When a gateway function equipped ECU has memorized the ECUs that are connected to the non-bus 2, if any of the ECUs connected to the gateway function equipped ECU has a communication error, the background color changes to yellow or red. (The displayed name will not disappear.)

Text in Illustration
*a	Not displayed or background color changes to red

Text in Illustration
*a	Background color changes to red

If both of the bus 2 main bus lines are open, ECUs or sensors that are located farther away from the network gateway ECU than the open part will be displayed as a communication stop on the CAN Bus Check screen.

(In this case, ECU D and E are not displayed or their background color changes to red.)

Text in Illustration
*a	Bus 2	*b	Non-bus 2
*c	V Bus	*d	Terminating Resistor
*e	Location of Malfunction	*f	Not displayed or background color changes to red or yellow
*g	CAN Bus Check Screen	*h	Central Gateway ECU (Network Gateway ECU)

Tech Tips

If a communication error occurs in an ECU, it is not displayed on the CAN Bus Check screen even though the ECU is present.

If both of the non-bus 2 main bus lines are open, ECUs that are located farther away from the network gateway ECU than the open part will be displayed as a communication stop on the CAN Bus Check screen.

(In this case, ECU I and J are not displayed or their background color changes to red.)

Text in Illustration
*a	Bus 2	*b	Non-bus 2
*c	V Bus	*d	Terminating Resistor
*e	Location of Malfunction	*f	Not displayed or background color changes to red or yellow
*g	CAN Bus Check Screen	*h	Central Gateway ECU (Network Gateway ECU)

Text in Illustration
*a	When any of the following malfunctions occur on the bus 2
*b	When any of the following malfunctions occur on a non-bus 2
*c	Not displayed

When any of the following malfunctions occur, CAN communication cannot be established and almost all ECUs and sensors on the bus show a communication error on the CAN Bus Check screen.

Details of Malfunction
Short between CAN lines (CANH and CANL)
Short between a CAN line (CANH or CANL) and +B
Short between a CAN line (CANH or CANL) and ground
Open in a CAN main bus line

Tech Tips

When a malfunction occurs on the bus 2, almost all ECUs and sensors in the bus 2 and non-bus 2 indicate a communication error (almost all ECUs are not displayed). As communication with the gateway function equipped ECU that is connected to the bus 2 stops, communication from the ECUs connected to the non-bus 2 that is monitored by the gateway function equipped ECU also stops (these ECUs are not displayed).
When a malfunction occurs in a non-bus 2, almost all ECUs connected to the non-bus 2 indicate a communication error.
A communication error in a non-bus 2 does not affect the bus 2 or other buses.
The malfunctioning part can be determined by checking for a short circuit between CAN bus lines or between a CAN bus line and ground or +B short using an electrical tester.

DTC TABLE BY ECU

Tech Tips

In the CAN communication system, the CAN communication DTCs of each ECU can be displayed using the GTS.
If CAN communication system DTCs are output, the malfunction cannot be determined only by the DTCs. Perform troubleshooting according to How to Proceed with Troubleshooting Click here.
If system function temporarily returns to normal, DTCs may not be output again even though the following DTC check procedures are used.

Hybrid Vehicle Control ECU / GTS Display "Hybrid Control"

Hybrid Vehicle Control ECU / GTS Display "Hybrid Control"
DTC	Detection Item	DTC Detection Condition	DTC Detection Pre-condition	DTC Check Procedure	Warning Indication in Meter	DTC Storage Method
U0100	Lost Communication with ECM/PCM "A"	The hybrid vehicle control ECU does not receive data from the ECM for 0.68 seconds or more.	Both conditions are met: The power switch is on (IG) for 1 second or more. The power source voltage of the hybrid vehicle control ECU is 9.5 V or more.	Turn the power switch on (IG) and wait at least 1.68 seconds.	HV system warning light turns on.	DTC is stored until it is cleared using the GTS.
U0110*1	Lost Communication with Drive Motor Control Module ''A''	Either condition is met: The hybrid vehicle control ECU does not receive data from the MG ECU for 0.11 seconds or more. The hybrid vehicle control ECU does not send data to the MG ECU for 0.04 seconds or more.	Both conditions are met: The power switch is on (IG) for 0.1 seconds or more. The power source voltage of the hybrid vehicle control ECU is 9.5 V or more.	Turn the power switch on (IG) and wait at least 0.21 seconds.	HV system warning light turns on.	DTC is stored until it is cleared using the GTS.
U0129	Lost Communication with Brake System Control Module	The hybrid vehicle control ECU does not receive data from the brake booster with master cylinder assembly (skid control ECU) for 2.34 seconds or more.	Both conditions are met: The power switch is on (IG) for 2 seconds or more. The power source voltage of the hybrid vehicle control ECU is 9.5 V or more.	Turn the power switch on (IG) and wait at least 4.34 seconds.	HV system warning light turns on.	DTC is stored until it is cleared using the GTS.
U0140	Communication Error from Body ECU to HV ECU	The hybrid vehicle control ECU does not receive data from the main body ECU (multiplex network body ECU) for 3.6 seconds or more.	Both conditions are met: The power switch is on (IG) for 1 second or more. The power source voltage of the hybrid vehicle control ECU is 9.5 V or more.	Turn the power switch on (IG) and wait at least 4.6 seconds.	HV system warning light turns on.	DTC is stored until it is cleared using the GTS.
U0151	Communication Error from Airbag ECU to HV ECU	The hybrid vehicle control ECU does not receive data from the airbag ECU assembly for 10.6 seconds or more.	Both conditions are met: The power switch is on (IG) for 1 second or more. The power source voltage of the hybrid vehicle control ECU is 9.5 V or more.	Turn the power switch on (IG) and wait at least 11.6 seconds.	HV system warning light turns on.	DTC is stored until it is cleared using the GTS.
U0164	Communication Error from A/C ECU to HV ECU	The hybrid vehicle control ECU does not receive data from the air conditioning amplifier assembly for 10.6 seconds or more.	Both conditions are met: The power switch is on (IG) for 1 second or more. The power source voltage of the hybrid vehicle control ECU is 9.5 V or more.	Turn the power switch on (IG) and wait at least 11.6 seconds.	-	DTC is stored until it is cleared using the GTS.
U029A*2	Lost Communication with Hybrid Battery Pack Sensor Module	The hybrid vehicle control ECU does not receive data from the battery smart unit for 0.52 seconds or more.	The power switch is on (IG) for 0.5 seconds or more.	Turn the power switch on (IG) and wait at least 1.02 seconds.	HV system warning light turns on.	DTC is stored until it is cleared using the GTS.
U0424*1	Invalid Data Received from HVAC Control Module	The hybrid vehicle control ECU receives an abnormal operation value command from the air conditioning amplifier assembly for 3 seconds or more.	Both conditions are met: The power switch is on (IG) for 1 second or more. The power source voltage of the hybrid vehicle control ECU is 9.5 V or more.	Turn the power switch on (IG) and wait at least 4 seconds.	-	DTC is stored until it is cleared using the GTS.
U1104*3	Lost Communication with Driving Support ECU	The hybrid vehicle control ECU does not receive data from the driving support ECU assembly for 1.02 seconds or more.	All conditions are met: The power switch is on (IG) for 2.1 seconds or more. The power source voltage of the hybrid vehicle control ECU is 9.5 V or more. Vehicle speed is 36 km/h (22 mph) or more.	Drive the vehicle at a speed of 36 km/h (22 mph) or more for at least 3.12 seconds.	HV system warning light turns on.	DTC is stored until it is cleared using the GTS.
U1107	Lost Communication with Power Management Module	The hybrid vehicle control ECU does not receive data from the certification ECU (smart key ECU assembly) for 3.6 seconds or more.	Both conditions are met: The power switch is on (IG) for 1 second or more. The power source voltage of the hybrid vehicle control ECU is 9.5 V or more.	Turn the power switch on (IG) and wait at least 4.6 seconds.	HV system warning light turns on.	DTC is stored until it is cleared using the GTS.

Tech Tips

This ECU uses the CAN communication system for DTC communication.
The hybrid vehicle control ECU stores DTCs for the dynamic radar cruise control system.
*1: Refer to Hybrid Control System Click here.
*2: Refer to Hybrid Battery System Click here.
*3: Dynamic radar cruise control system DTC.

Hybrid Vehicle Control ECU / GTS Display "Cruise Control"

Hybrid Vehicle Control ECU / GTS Display "Cruise Control"
DTC	Detection Item	DTC Detection Condition	DTC Detection Pre-condition	DTC Check Procedure	Warning Indication in Meter	DTC Storage Method
U0122	Lost Communication with Vehicle Dynamic Control Module	While the cruise control system is on (the system has been switched on using the ON/OFF button on the cruise control switch), the hybrid vehicle control ECU does not receive data from the brake booster with master cylinder assembly (skid control ECU) for 2.73 seconds or more.	Both conditions are met: The power switch is on (IG) for 2.1 seconds or more. The power source voltage of the hybrid vehicle control ECU is 9.5 V or more.	After turning the power switch on (IG), turn the cruise control main switch on and wait for at least 4.83 seconds.	Cruise control indicator light (amber) illuminates. Displays messages on the multi-information display.	DTC is stored until it is cleared using the GTS.

Tech Tips

This ECU uses the CAN communication system for DTC communication.
The hybrid vehicle control ECU stores DTCs for the cruise control system.

ECM / GTS Display "Engine and ECT"

ECM / GTS Display "Engine and ECT"
DTC	Detection Item	DTC Detection Condition	DTC Detection Pre-condition	DTC Check Procedure	Warning Indication in Meter	DTC Storage Method
U0293	Lost Communication with HV ECU	The ECM does not receive data from the hybrid vehicle control ECU for 0.576 seconds or more.	Both conditions are met: The power switch is on (IG) for 1 second or more. The power source voltage of the ECM is 10.5 V or more.	Turn the power switch on (IG) and wait at least 1.576 seconds.	-	DTC is stored until it is cleared using the GTS.

Tech Tips