2001 TOYOTA SEQUOIA ECU

DIDI5±01
F19740
F19741
F19742
± DIAGNOSTICSCAN COMMUNICATION SYSTEM
DI±1073
1267 Author: Date:
2005 SEQUOIA (RM1146U)
DIAGNOSIS SYSTEM
1. BUS CHECK
HINT:
The ECUs that are properly connected to the CAN communica-
tion system can be displayed using the hand±held tester via
CAN VIM.
(a) Select ºBUS CHECKº from the ºOBD/MOBD MENUº
screen.
(b) Press ºENTERº on the hand±held tester via CAN VIM.
(c) The screen displays the ECUs and sensors that are prop-
erly connected to the CAN communication system.
HINT:
There is a communication stop in the system of any properly
connected ECUs or sensors that are not displayed
(see page DI±1067).

DIDI6±01
Action when unable to communicateDTC detection
(Driver detectable)
Suspension
Control ECUVSC/TRC function stops
[When unable to communicate with ECM]
Function stops (Vehicle height cannot be changed until the ignition
switch is turned off)
[When unable to communicate with Translate ECU]
Vehicle height is maintained at the normal level until the ignition
switch is turned off. If communication is still impossible even after
the ignition switch is turned on again, the same height is maintained.Not detectable
( )
Not detectable
(VSC warning lamp
comes on)
Detectable
(Only DTCs are stored) ECMTranslate ECU
Suspension Control ECU
Rx
TxTx
Rx
Tx TxTx
Rx

ECM
Translate ECU DI±1074
± DIAGNOSTICSCAN COMMUNICATION SYSTEM
1268 Author: Date:
2005 SEQUOIA (RM1146U)
FAIL±SAFE CHART
1. FAIL±SAFE FUNCTION
(a) When communication fails in any of the CAN bus lines (communication lines) due to a short circuit or
any other cause, the fail±safe function, which is specified for each system, operates to prevent the
system from malfunctioning.
(b) Effects on each system when communication is impossible are as follows.
HINT:

Rx: Reception from each ECU.

Tx: Transmission to each ECU.

DIDI7±01
± DIAGNOSTICSCAN COMMUNICATION SYSTEM
DI±1075
1269 Author: Date:
2005 SEQUOIA (RM1146U)
DIAGNOSTIC TROUBLE CODE CHART
1. DTC TABLE BY ECU
HINT:

If CAN communication system DTCs are output, trouble cannot be determined only by the DTCs. Per-
form troubleshooting according to ºHOW TO PROCEED WITH TROUBLESHOOTINGº (see page
DI±1065).
(a) Skid Control ECU
HINT:

DTC communication uses the SIL line.

If C1201/51, C1202/52 or C1203/53 is output from skid control ECU, perform troubleshooting of each
diagnosis code (see page DI±921).
DTC No.Detection Item
U0100/65Lost Communication With ECM/PCM ºAº
(b) ECM
HINT:
The ECM is connected to the CAN communication system, but CAN communication system DTCs are not
output.
(c) Translate ECU
HINT:
The translate ECU outputs DTCs only via the BRAKE warning light. Therefore, the DTCs cannot be checked
on the hand±held tester display via the CAN VIM.
DTC No.Detection Item
65Abnormalities in EFI communication
94Abnormalities in CAN communication
(d) Suspension Control ECU
HINT:
DTC communication uses the SIL line.
DTC No.Detection Item
U0100/65Lost Communication With ECM/PCM ºAº
U0122/67Lost Communication With Vehicle Dynamics Control Module
U0132/74Lost Communication With Ride Level Control Module

DIDI8±01
F19697
Translate ECU
Junction ConnectorECM
ENG+
ENG±14
T5
16
T51
J55
2
J55 R
W1
J53
2
J5333
E5
34
E5 W L CANH
CANL
Suspension Control ECU
CANH
CANL29
S25
28
S25G
W (*1)
(*1)1
J56
2
J561
J54
2
J54W B
6
14D6 DLC3
CANH
CANL
Instrument Panel J/B
BAT
CG W±R 13
1F 1
1L W W
8
5
B16
4 O
A
A
OJ43
J/C
IG ALT F10
FL Block
Battery
*1: w/ Air Suspension SystemOBD
12 DI±1076
± DIAGNOSTICSCAN COMMUNICATION SYSTEM
1270 Author: Date:
2005 SEQUOIA (RM1146U)
CIRCUIT INSPECTION
Check CAN Bus Line
CIRCUIT DESCRIPTION
When any DTC of the CAN communication system is output, first measure the resistance between the termi-
nals of the DLC3 and the suspension control ECU connector to specify the trouble area.
WIRING DIAGRAM

F19698
ECM
MREL 8
E4 B±W 14
IA4 B±W
B±R12
IA4B±R B±R
B±R J16
J/C
D
DD1
E4
2
E4+B
+B2 Engine Room J/B
EF1 Relay
2
2H
6
2H1
2D
1
2F 3
25
1B
W±B
W±B
W±B7
E8E01
EB
EDJ5
J/C A F10
FL Block
B
4
5 B
BatteryEF1 No.1
± DIAGNOSTICSCAN COMMUNICATION SYSTEM
DI±1079
1273 Author: Date:
2005 SEQUOIA (RM1146U)
ECM Communication Stop Mode
MODE DESCRIPTION
Detection ItemSymptomTrouble Area
ECM Communica-
tion Stop Mode

ºENGINEº is not displayed on the ºBUS CHECKº screen
of the hand±held tester.

DTCs are output from each ECU in ECM communication
stop mode as shown in the ºDTC COMBINATION TABLEº
(see page DI±1067).

Power source or inside the ECM
WIRING DIAGRAM
DIDI9±01

F19699
Translate ECU
IG1 1
T5 B±R A
J37 J/B
A
J37 B±R Sub J/B No.3
8
3C 8
3A B±R
Instrument Panel J/B
ECU±IG
4
1C
6
1C 4
1F
1
1LAM1
2 1B±Y
2I18
Ignition SW
W±L
1
IG1AM1
W
8
5
BALTF10
FL Block
Battery40
T5 O
A
A
OJ43
J/C
IGGND
± DIAGNOSTICSCAN COMMUNICATION SYSTEM
DI±1081
1275 Author: Date:
2005 SEQUOIA (RM1146U)
Translate ECU Communication Stop Mode
MODE DESCRIPTION
Detection ItemSymptomTrouble Area
Translate ECU
Communication
Stop Mode

ºTRANSLATE ECUº is not displayed on the ºBUS
CHECKº screen of the hand±held tester.

DTCs are output from each ECU in translate ECU com-
munication stop mode as shown in the ºDTC COMBINA-
TION TABLEº (see page DI±1067).

Power source or inside the translate ECU
WIRING DIAGRAM
DIDIA±01

F19152
IG1
T5
Translate ECU Wire Harness View:
GND
DI±1082
± DIAGNOSTICSCAN COMMUNICATION SYSTEM
1276 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
1 Check wire harness (Translate ECU ± Battery and Translate ECU ± Body ground).
PREPARATION:
Disconnect the translate ECU connector.
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:
Tester connectionConditionSpecified value
T5±40 (GND) ±
Body groundAlwaysBelow 1 W
CHECK:
Measure the voltage according to the value(s) in the table be-
low.
OK:
Tester connectionConditionSpecified value
T5±1 (IG1) ±
Body groundIgnition Switch ON10 to 14 V
NG Repair or replace wire harness or connector
(Translate ECU ± Battery or Translate ECU ±
Body ground).
OK
Replace translate ECU.

F19706
Suspension
Control ECU
IG 10
S25 B±R
J37 J/C
J37 Sub J/B No.3
B±R 8
3C 8
3A B±R
Instrument Panel J/B
4
1F
1
1LECU±IG
AM14
1C
6
1CB±Y
2I18
Ignition SW
AM1
IG1W±L
W
8
ALT
5
B
BatteryF10
FL BlockGND 22
S25 W±B
A
J12
J/C
IF 121 AA
Translate ECU
ENG+
ENG±T5
T514
16ECM
CANH
CANL
Junction Connector
E5
E5 33
34 R
W
WL
J55
J55J53
J53 1
21
2 J56
J561
2
W G
CANH
CANL S25
S2529
28
± DIAGNOSTICSCAN COMMUNICATION SYSTEM
DI±1083
1277 Author: Date:
2005 SEQUOIA (RM1146U)
Suspension Control ECU Communication Stop Mode
MODE DESCRIPTION
Detection ItemSymptomTrouble Area
Suspension Con-
trol ECU Commu-
nication Stop
Mode
ºRIAR AIRSUSº is not displayed on the ºBUS CHECKº
screen of the hand±held tester.

DTCs are output from each ECU in suspension control
ECU communication stop mode in the ºDTC COMBINA-
TION TABLEº (see page DI±1067).

Power source or inside the suspension control ECU

Suspension control ECU sub bus line
WIRING DIAGRAM
DIDIB±01