Toyota 4Runner: Lost Communication with Gateway Module (U1002)

Toyota 4Runner Service Manual / Power Source / Network / Networking / Can Communication System / 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.
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 circuit Front power seat switch LH branch wire or connector Main body ECU (multiplex network body ECU) main wire or connector Combination meter assembly main wire or connector Front power seat switch LH Main body ECU (multiplex network body ECU) Combination meter assembly No. 2 junction connector

HINT:

For vehicles with seat position memory 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 the 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 CAN BUS WIRE (MAIN WIRE FOR DISCONNECTION, BUS LINE FOR SHORT CIRCUIT)

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

Standard Resistance:

Tester Connection	Switch Condition	Specified Condition	Resistance: Malfunction
F10-9 (CANP) - F10-10 (CANN)	Ignition switch off	54 to 69 Ω	Below 54 Ω: Short in line
F10-9 (CANP) - F10-10 (CANN)	Ignition switch off	54 to 69 Ω	Higher than 69 Ω: Open in CAN main bus line
F10-9 (CANP) - F13-16 (BAT)	Ignition switch off	6 kΩ or higher	Below 6 kΩ: +B short
F10-10 (CANN) - F13-16 (BAT)	Ignition switch off	6 kΩ or higher	Below 6 kΩ: +B short
F10-9 (CANP) - F13-4 (CG)	Ignition switch off	200 Ω or higher	Below 200 Ω: Ground short
F10-10 (CANN) - F13-4 (CG)	Ignition switch off	200 Ω or higher	Below 200 Ω: Ground short

Text in Illustration

Component with harness connected

(Main Body ECU (Multiplex Network Body ECU))

Front view of DLC3

Result

Proceed to

- Open in CAN main bus line

- Short in line

- +B short

- Ground short

GO TO STEP 9

GO TO STEP 18

3.	CHECK FOR OPEN IN CAN BUS MAIN WIRE (NO. 2 JUNCTION CONNECTOR - COMBINATION METER ASSEMBLY)

(a) Disconnect the F93 No. 2 junction connector connector.

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

Standard Resistance:

Tester Connection	Switch Condition	Specified Condition
F93-2 (MSCH) - F93-13 (MSCL)	Ignition switch off	108 to 132 Ω

Text in Illustration

*a	Rear view of wire harness connector (to No. 2 Junction Connector)

GO TO STEP 5

4.	CHECK FOR OPEN IN CAN BUS MAIN WIRE (NO. 2 JUNCTION CONNECTOR - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU))

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

Standard Resistance:

Tester Connection	Switch Condition	Specified Condition
F93-1 (CANP) - F93-12 (CANN)	Ignition switch off	108 to 132 Ω

Text in Illustration

*a	Rear view of wire harness connector (to No. 2 Junction Connector)

REPAIR OR REPLACE NO. 2 JUNCTION CONNECTOR

GO TO STEP 7

5.	CONNECT CONNECTOR

(a) Reconnect the F93 No. 2 junction connector connector.

6.	CHECK FOR OPEN IN CAN BUS MAIN WIRE (COMBINATION METER ASSEMBLY - NO. 2 JUNCTION CONNECTOR)

(a) Disconnect the F14 combination meter assembly connector.

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

Standard Resistance:

Tester Connection	Switch Condition	Specified Condition
F14-23 (MSCH) - F14-24 (MSCL)	Ignition switch off	108 to 132 Ω

Text in Illustration

*a	Front view of wire harness connector (to Combination Meter Assembly)

REPLACE COMBINATION METER ASSEMBLY

REPAIR OR REPLACE CAN MAIN WIRE CONNECTED TO (COMBINATION METER ASSEMBLY - NO. 2 JUNCTION CONNECTOR)

7.	CONNECT CONNECTOR

(a) Reconnect the F93 No. 2 junction connector connector.

8.	CHECK FOR OPEN IN CAN BUS MAIN WIRE (MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) - NO. 2 JUNCTION CONNECTOR)

(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))

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

REPAIR OR REPLACE CAN MAIN WIRE CONNECTED TO (MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) - NO. 2 JUNCTION CONNECTOR)

9.	CHECK FOR SHORT IN CAN BUS WIRES (NO. 2 JUNCTION CONNECTOR - FRONT POWER SEAT SWITCH LH)

(a) Disconnect the F93 No. 2 junction connector connector.

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

Standard Resistance:

Tester Connection	Switch Condition	Specified Condition
F93-3 (CANP) - F93-14 (CANN)	Ignition switch off	200 Ω or higher
F93-3 (CANP) - F13-4 (CG)	Ignition switch off	200 Ω or higher
F93-14 (CANN) - F13-4 (CG)	Ignition switch off	200 Ω or higher
F93-3 (CANP) - F13-16 (BAT)	Ignition switch off	6 kΩ or higher
F93-14 (CANN) - F13-16 (BAT)	Ignition switch off	6 kΩ or higher

Text in Illustration

Rear view of wire harness connector

(to No. 2 Junction Connector)

Front view of DLC3

GO TO STEP 12

10.	CHECK FOR SHORT IN CAN BUS WIRES (NO. 2 JUNCTION CONNECTOR - COMBINATION METER ASSEMBLY)

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

Standard Resistance:

Tester Connection	Switch Condition	Specified Condition
F93-2 (MSCH) - F93-13 (MSCL)	Ignition switch off	108 to 132 Ω
F93-2 (MSCH) - F13-4 (CG)	Ignition switch off	200 Ω or higher
F93-13 (MSCL) - F13-4 (CG)	Ignition switch off	200 Ω or higher
F93-2 (MSCH) - F13-16 (BAT)	Ignition switch off	6 kΩ or higher
F93-13 (MSCL) - F13-16 (BAT)	Ignition switch off	6 kΩ or higher

Text in Illustration

Rear view of wire harness connector

(to No. 2 Junction Connector)

Front view of DLC3

GO TO STEP 14

11.	CHECK FOR SHORT IN CAN BUS WIRES (NO. 2 JUNCTION CONNECTOR - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU))

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

Standard Resistance:

Tester Connection	Switch Condition	Specified Condition
F93-1 (CANP) - F93-12 (CANN)	Ignition switch off	108 to 132 Ω
F93-1 (CANP) - F13-4 (CG)	Ignition switch off	200 Ω or higher
F93-12 (CANN) - F13-4 (CG)	Ignition switch off	200 Ω or higher
F93-1 (CANP) - F13-16 (BAT)	Ignition switch off	6 kΩ or higher
F93-12 (CANN) - F13-16 (BAT)	Ignition switch off	6 kΩ or higher

Text in Illustration

Rear view of wire harness connector

(to No. 2 Junction Connector)

Front view of DLC3

REPAIR OR REPLACE NO. 2 JUNCTION CONNECTOR

GO TO STEP 16

12.	CONNECT CONNECTOR

(a) Reconnect the F93 No. 2 junction connector connector.

13.	CHECK FOR SHORT IN CAN BUS WIRES (FRONT POWER SEAT SWITCH LH)

(a) Disconnect the b19 front power seat switch LH connector.

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

Standard Resistance:

Tester Connection	Switch Condition	Specified Condition
b19-8 (CANP) - b19-7 (CANN)	Ignition switch off	54 to 69 Ω
b19-8 (CANP) - F13-4 (CG)	Ignition switch off	200 Ω or higher
b19-7 (CANN) - F13-4 (CG)	Ignition switch off	200 Ω or higher
b19-8 (CANP) - F13-16 (BAT)	Ignition switch off	6 kΩ or higher
b19-7 (CANN) - F13-16 (BAT)	Ignition switch off	6 kΩ or higher

Text in Illustration

Rear view of wire harness connector

(to Front Power Seat Switch LH)

Front view of DLC3

REPLACE FRONT POWER SEAT SWITCH LH

REPAIR OR REPLACE FRONT POWER SEAT SWITCH LH CAN BRANCH WIRE OR CONNECTOR (CANP, CANN)

14.	CONNECT CONNECTOR

(a) Reconnect the F93 No. 2 junction connector connector.

15.	CHECK FOR SHORT IN CAN BUS WIRES (COMBINATION METER ASSEMBLY)

(a) Disconnect the F14 combination meter assembly connector.

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

Standard Resistance:

Tester Connection	Switch Condition	Specified Condition
F14-23 (MSCH) - F14-24 (MSCL)	Ignition switch off	108 to 132 Ω
F14-23 (MSCH) - F13-4 (CG)	Ignition switch off	200 Ω or higher
F14-24 (MSCL) - F13-4 (CG)	Ignition switch off	200 Ω or higher
F14-23 (MSCH) - F13-16 (BAT)	Ignition switch off	6 kΩ or higher
F14-24 (MSCL) - F13-16 (BAT)	Ignition switch off	6 kΩ or higher

Text in Illustration

Front view of wire harness connector

(to Combination Meter Assembly)

Front view of DLC3

REPLACE COMBINATION METER ASSEMBLY

REPAIR OR REPLACE COMBINATION METER ASSEMBLY CAN MAIN WIRE OR CONNECTOR (MSCH, MSCL)

16.	CONNECT CONNECTOR

(a) Reconnect the F93 No. 2 junction connector connector.

17.	CHECK FOR SHORT IN CAN BUS WIRES (MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU))

(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
F10-9 (CANP) - F13-4 (CG)	Ignition switch off	200 Ω or higher
F10-10 (CANN) - F13-4 (CG)	Ignition switch off	200 Ω or higher
F10-9 (CANP) - F13-16 (BAT)	Ignition switch off	6 kΩ or higher
F10-10 (CANN) - F13-16 (BAT)	Ignition switch off	6 kΩ or higher

Text in Illustration

Rear view of wire harness connector

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

Front view of DLC3

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

REPAIR OR REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) MAIN WIRE OR CONNECTOR (CANP, CANN)

18.	CHECK HARNESS AND CONNECTOR (MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) - BATTERY AND GROUND)

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

(b) Reconnect the driver side junction block assembly connectors.

NOTICE:

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

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))

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

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

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A-30 (BECU) - Body ground	Always	11 to 14 V
A-31 (ALTB) - 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

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