CAN COMMUNICATION SYSTEM(for RHD with Entry and Start System), Diagnostic DTC:U1002

DTC Code	DTC Name
U1002	Lost Communication with Gateway Module (Sensor Bus)

DESCRIPTION

The driving support ECU assembly stores this DTC when no signals can be received from the ECUs that have been memorized as those connected to the parking assist bus.
When the driving support ECU assembly receives a response signal from the ECUs connected to the parking assist bus, the driving support ECU assembly recognizes and memorizes that the ECU is connected to the parking assist bus. Based on this memorized data, the driving support ECU assembly monitors for malfunctions in the ECUs connected to the parking assist bus when communicating with those ECUs. If the driving support ECU assembly cannot receive response signals from the ECUs that have been memorized as those connected to the parking assist bus, the driving support ECU assembly determines that a malfunction exists.
If 2 or more DTCs are output during the DTC check, one side of the CAN branch wire may be open (one side of the CANH [CAN branch wire]/CANL [CAN branch wire] of the ECU and/or sensor is open).

DTC Code	DTC Detection Condition	Trouble Area
U1002	Lost communication with the gateway module (parking assist bus).	Parking assist bus circuit Driving support ECU assembly CAN main wire or connector Millimeter wave radar sensor assembly CAN main wire or connector Driving support ECU assembly Millimeter wave radar sensor assembly

For vehicles with a pre-crash safety system.

WIRING DIAGRAM


*a	Millimeter Wave Radar Sensor Assembly
*b	Driving Support ECU Assembly

CAUTION / NOTICE / HINT

Tech Tips

Operating the engine switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.

PROCEDURE

DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL
1. Disconnect the cable from the negative (-) battery terminal before measuring the resistances of the CAN main wire and CAN branch wire.
  
  CAUTION:
  
  Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the airbag system.
  Note
  - After turning the engine 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.
  - When disconnecting the cable, some systems need to be initialized after the cable is reconnected Click here.
NEXT

CHECK FOR CAN BUS WIRE (CAN MAIN WIRE FOR DISCONNECTION, BUS LINE FOR SHORT CIRCUIT)

Text in Illustration
*a	Component with harness connected (Driving Support ECU Assembly)
*b	Front view of DLC3

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

Standard Resistance

Tester Connection	Switch Condition	Specified Condition	resistance: Malfunction
G119-40 (CA1P) - G119-18 (CA1N)	Engine switch off	54 to 69 Ω	Below 53 Ω: Short in line
G119-40 (CA1P) - G119-18 (CA1N)	Engine switch off	54 to 69 Ω	Higher than 70 Ω: Open in CAN main bus line
G119-40 (CA1P) - G48-16 (BAT)	Engine switch off	6 kΩ or higher	Below 6 kΩ: +B short
G119-18 (CA1N) - G48-16 (BAT)	Engine switch off	6 kΩ or higher	Below 6 kΩ: +B short
G119-40 (CA1P) - G48-4 (CG)	Engine switch off	200 Ω or higher	Below 200 Ω: Ground short
G119-18 (CA1N) - G48-4 (CG)	Engine switch off	200 Ω or higher	Below 200 Ω: Ground short

Result
Result	Proceed to
NG Open in CAN main wire	A
NG Short in line +B short Ground short	B
OK	C

CHECK FOR SHORT IN CAN BUS WIRES (DRIVING SUPPORT ECU ASSEMBLY - MILLIMETER WAVE RADAR SENSOR ASSEMBLY) Click here

CHECK HARNESS AND CONNECTOR (DRIVING SUPPORT ECU ASSEMBLY - BATTERY AND BODY GROUND) Click here

CHECK FOR OPEN IN CAN BUS MAIN WIRE (DRIVING SUPPORT ECU ASSEMBLY - MILLIMETER WAVE RADAR SENSOR ASSEMBLY)

Text in Illustration

*a
Rear view of wire harness connector

(to Driving Support ECU Assembly)

Disconnect the G119 driving support ECU assembly connector.

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

Standard Resistance

Tester Connection	Switch Condition	Specified Condition
G119-40 (CA1P) - G119-18 (CA1N)	Engine switch off	108 to 132 Ω

REPLACE DRIVING SUPPORT ECU ASSEMBLY Click here

CONNECT CONNECTOR
1. Reconnect the G119 driving support ECU assembly connector.
NEXT

CHECK FOR OPEN IN CAN BUS MAIN WIRE (MILLIMETER WAVE RADAR SENSOR ASSEMBLY - DRIVING SUPPORT ECU ASSEMBLY)

Text in Illustration

*a
Front view of wire harness connector

(to Millimeter Wave Radar Sensor Assembly)

Disconnect the A15 millimeter wave radar sensor assembly connector.

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

Standard Resistance

Tester Connection	Switch Condition	Specified Condition
A15-4 (CA1P) - A15-3 (CA1N)	Engine switch off	108 to 132 Ω

REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY Click here

REPAIR OR REPLACE CAN MAIN WIRE CONNECTED TO MILLIMETER WAVE RADAR SENSOR (MILLIMETER WAVE RADAR SENSOR - DRIVING SUPPORT ECU ASSEMBLY)

CHECK FOR SHORT IN CAN BUS WIRES (DRIVING SUPPORT ECU ASSEMBLY - MILLIMETER WAVE RADAR SENSOR ASSEMBLY)

Text in Illustration
*a	Rear view of wire harness connector (to Driving Support ECU Assembly)
*b	Front view of DLC3

Disconnect the G119 driving support ECU assembly connector.

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

Standard Resistance

Tester Connection	Switch Condition	Specified Condition
G119-40 (CA1P) - G119-18 (CA1N)	Engine switch off	108 to 132 Ω
G119-40 (CA1P) - G48-4 (CG)	Engine switch off	200 Ω or higher
G119-18 (CA1N) - G48-4 (CG)	Engine switch off	200 Ω or higher
G119-40 (CA1P) - G48-16 (BAT)	Engine switch off	6 kΩ or higher
G119-18 (CA1N) - G48-16 (BAT)	Engine switch off	6 kΩ or higher

REPLACE DRIVING SUPPORT ECU ASSEMBLY Click here

CONNECT CONNECTOR
1. Reconnect the G119 driving support ECU assembly connector.
NEXT

CHECK FOR SHORT IN CAN BUS WIRES (MILLIMETER WAVE RADAR SENSOR ASSEMBLY - DRIVING SUPPORT ECU ASSEMBLY)

Text in Illustration
*a	Front view of wire harness connector (to Millimeter Wave Radar Sensor Assembly)
*b	Front view of DLC3

Disconnect the A15 millimeter wave radar sensor assembly connector.

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

Standard Resistance

Tester Connection	Switch Condition	Specified Condition
A15-4 (CA1P) - A15-3 (CA1N)	Engine switch off	108 to 132 Ω
A15-4 (CA1P) - G48-4 (CG)	Engine switch off	200 Ω or higher
A15-3 (CA1N) - G48-4 (CG)	Engine switch off	200 Ω or higher
A15-4 (CA1P) - G48-16 (BAT)	Engine switch off	6 kΩ or higher
A15-3 (CA1N) - G48-16 (BAT)	Engine switch off	6 kΩ or higher

REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY Click here

REPAIR OR REPLACE CAN MAIN WIRE CONNECTED TO MILLIMETER WAVE RADAR SENSOR (MILLIMETER WAVE RADAR SENSOR - DRIVING SUPPORT ECU ASSEMBLY)

CHECK HARNESS AND CONNECTOR (DRIVING SUPPORT ECU ASSEMBLY - BATTERY AND BODY GROUND)

Text in Illustration

*a
Rear view of wire harness connector

(to Driving Support ECU Assembly)

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 G119 driving support ECU assembly connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
G119-25 (GND) - Body ground	Always	Below 1 Ω

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

Standard Voltage

Tester Connection	Switch Condition	Specified Condition
G119-30 (B) - Body ground	Engine switch on (IG)	11 to 14 V

REPLACE DRIVING SUPPORT ECU ASSEMBLY Click here

REPAIR OR REPLACE HARNESS OR CONNECTOR