Toyota Tundra. Manual — part 276

Standard voltage

STANDARD VOLTAGE SPECIFICATION TABLE

Fig. 35: Identifying Z9 And Z10 Front Power Seat Control ECU And Switch LH Connector
Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: REPLACE POSITION CONTROL ECU AND SWITCH ASSEMBLY (See REMOVAL )

DTC U1002: LOST COMMUNICATION WITH GATEWAY MODULE

DESCRIPTION

If 2 or more DTCs are output during the DTC check, one side of the CAN branch wire may he open. (One side
of the CANH [branch wire]/CANL [branch wire] of the ECU and/or sensor is open.)

Tester Connection Switch Condition

Specified

Condition

Z9-5 (+B) - Body

ground

Always

11 to 14 V

Z10-8 (SYSB) -

Body ground

Z10-4 (IG) - Body

ground

Ignition switch ON

2009 Toyota Tundra

2009 ACCESSORIES & EQUIPMENT CAN Communication - Tundra

DTC TABLE

WIRING DIAGRAM

DTC

Code

Symptom

Trouble Area

U1002

Lost communication with gateway
module



MS bus circuit



Front power seat control ECU and switch LH branch
wire or connector



Multiplex tilt and telescopic ECU branch wire or
connector



Outer mirror control ECU branch wire or connector



Combination meter ECU main wire or connector



Main body ECU main wire or connector



Front power seat control ECU and switch LH



Multiplex tilt and telescopic ECU



Outer mirror control ECU



Combination meter ECU



Main body ECU



No. 3 junction connector

2009 Toyota Tundra

2009 ACCESSORIES & EQUIPMENT CAN Communication - Tundra

Fig. 36: Identifying Lost Communication With Gateway Module - Wiring Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

INSPECTION 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.

2. CHECK CAN BUS WIRE (MAIN WIRE FOR DISCONNECTION, BUS LINES FOR SHORT

CIRCUIT)

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

Standard resistance

STANDARD RESISTANCE SPECIFICATION TABLE

CAUTION: Wait at least 90 seconds after disconnecting the cable from the

negative (-) battery terminal to prevent airbag and seat belt
pretensioner activation.

NOTE:

After the ignition switch is turned OFF, the navigation system
requires approximately 90 seconds to record various types of
memory and settings. As a result, after turning the ignition switch
OFF, wait 90 seconds or more before disconnecting the cable from
the negative (-) battery terminal.

Tester

Connection

Switch

Condition

Specified

Condition

Resistance of

Malfunction

J28-22

(CANH) - J28-

21 (CANL)

Ignition switch

OFF

54 to 69 ohms

Below 53

ohms: Short in

line

70 ohms or

higher: Open

in CAN main

bus line

J28-22

(CANH) - J28-

18 (B)

Ignition switch

OFF

6 kohms

higher

Below 6

kohms: +B

short

J28-21

(CANL) - J28-

18 (B)

J28-22

(CANH) - J28-

40 (E1)

Ignition switch

OFF

200 ohms or

higher

Below 200

ohms: Ground

short

J28-21

2009 Toyota Tundra

2009 ACCESSORIES & EQUIPMENT CAN Communication - Tundra

Fig. 37: Identifying J28 Combination Meter ECU Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

Result

RESULT REFERENCE TABLE

B: Go to step 10

C: Go to step 29

A: Go to Next Step

3. CHECK FOR OPEN IN CAN BUS WIRE (NO. 3 JUNCTION CONNECTOR - MAIN BODY

ECU)

a. Disconnect the J97 No. 3 junction connector connector.

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

(CANL) - J28-

40 (E1)

Result

Proceed to

NG



Open in CAN main wire

A

NG



Short in line



+B short



Ground short

B

OK

C

2009 Toyota Tundra

2009 ACCESSORIES & EQUIPMENT CAN Communication - Tundra