Toyota 4Runner: Lost Communication with Gateway Module (MS Bus) (U1002,U1114)

Toyota 4Runner Service Manual / Power Source / Network / Networking / Can Communication System / Lost Communication with Gateway Module (MS Bus) (U1002,U1114)

DESCRIPTION

The main body ECU (multiplex network body ECU) stores this DTC when no signals can be received from the ECUs that are memorized as those connected to the CAN MS bus.
When the main body ECU (multiplex network body ECU) receives a response signal from the ECUs connected to the CAN MS bus, the main body ECU (multiplex network body ECU) recognizes and memorizes that the ECU is connected to the CAN MS bus. Based on this memorized data, the main body ECU (multiplex network body ECU) monitors for malfunctions in the ECUs connected to the CAN MS bus when communicating with those ECUs. If the main body ECU (multiplex network body ECU) cannot receive response signals from the ECUs that are memorized as those connected to the CAN MS bus, the main body ECU (multiplex network body ECU) 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 [branch wire]/CANL [branch wire] of the ECU and/or sensor is open).

DTC Code	DTC Detection Condition	Trouble Area
U1002	Lost communication with the gateway module (MS bus).	Power source or inside main body ECU (multiplex network body ECU) Power source or inside drive monitor switch CAN MS bus circuit Main body ECU (multiplex network body ECU) main wire or connector Drive monitor switch main wire or connector Main body ECU (multiplex network body ECU) Drive monitor switch
U1114	Lost communication with the main switch module.	Power source or inside main body ECU (multiplex network body ECU) Power source or inside drive monitor switch CAN MS bus circuit Main body ECU (multiplex network body ECU) main wire or connector Drive monitor switch main wire or connector Main body ECU (multiplex network body ECU) Drive monitor switch

HINT:

For vehicles with CRAWL control only.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

HINT:

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

PROCEDURE

1.	DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL

(a) Disconnect the cable from the negative (-) battery terminal before measuring the resistances of the main wire and branch wire.

CAUTION:

Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

NOTICE:

When disconnecting the cable, some systems need to be initialized after the cable is reconnected (See page ).

2.	CHECK FOR OPEN IN CAN BUS MAIN WIRE (MAIN BODY ECU - DRIVE MONITOR SWITCH)

(a) Disconnect the F10 main body ECU (multiplex network body ECU) connector.

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

Standard Resistance:

Tester Connection	Switch Condition	Specified Condition
F10-9 (CANP) - F10-10 (CANN)	Ignition switch off	108 to 132 Ω

Text in Illustration

*a	Rear view of wire harness connector (to Main Body ECU [Multiplex Network Body ECU])

GO TO STEP 4

3.	CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - BATTERY AND BODY GROUND)

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

Text in Illustration

Rear view of wire harness connector

(to Main Body ECU [Multiplex Network Body ECU])

Front view of wire harness connector

(to Main Body ECU [Multiplex Network Body ECU])

NOTICE:

When disconnecting the cable, some systems need to be initialized after the cable is reconnected (See page ).

(b) Remove the main body ECU (multiplex network body ECU) (See page ).

Standard Resistance:

Tester Connection	Condition	Specified Condition
F10-3 (GND2) - Body ground	Always	Below 1 Ω
A-11 (GND1) - Body ground	Always	Below 1 Ω

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
A-31 (ALTB) - Body ground	Always	11 to 14 V
A-30 (BECU) - Body ground	Always	11 to 14 V
A-29 (ACC) - Body ground	Ignition switch ACC	11 to 14 V
A-32 (IG) - Body ground	Ignition switch ON	11 to 14 V

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	CONNECT CONNECTOR

(a) Reconnect the F10 main body ECU (multiplex network body ECU) connector.

5.	CHECK FOR OPEN IN CAN BUS MAIN WIRE (DRIVE MONITOR SWITCH - MAIN BODY ECU)

(a) Disconnect the U1 drive monitor switch connector.

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

Standard Resistance:

Tester Connection	Switch Condition	Specified Condition
U1-1 (CANP) - U1-2 (CANN)	Ignition switch off	108 to 132 Ω

Text in Illustration

*a	Rear view of wire harness connector (to Drive Monitor Switch)

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (MAIN BODY ECU - DRIVE MONITOR SWITCH)

6.	CHECK HARNESS AND CONNECTOR (DRIVE MONITOR SWITCH - BATTERY AND BODY GROUND)

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

NOTICE:

When disconnecting the cable, some systems need to be initialized after the cable is reconnected (See page ).

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
U1-7 (GND) - Body ground	Always	Below 1 Ω

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
U1-6 (+B) - Body ground	Always	11 to 14 V
U1-12 (IG) - Body ground	Ignition switch ON	11 to 14 V

Text in Illustration

*a	Rear view of wire harness connector (to Drive Monitor Switch)

REPLACE DRIVE MONITOR SWITCH

REPAIR OR REPLACE HARNESS OR CONNECTOR

Lost Communication with Gateway Module (Power Management2) (U1002)

DESCRIPTION The power management control ECU stores this DTC when no signals can be received from the ECUs that are memorized as those connected to the power management bus. When t ...

Lost Communication with Gateway Module (U1002)

DESCRIPTION The main body ECU (multiplex network body ECU) stores this DTC when no signals can be received from the ECUs that are memorized as those connected to the CAN MS bus. Wh ...

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