Page 425 of 4323
B17411E8
IGT8
IGT2IGT4
IGT5 IGT6IGT3
IGT7IGT1E1(+)(±) (+) (+)
(+)
(+)
(+)
(+)
(+)
E6
± DIAGNOSTICSENGINE
DI±231
425 Author: Date:
2005 SEQUOIA (RM1146U)
6 Disconnect ignition coil with igniter connector, and check voltage between ter-
minals IGT1 ± IGT8 and E1 of ECM connector.
PREPARATION:
(a) Disconnect the I1, I2, I3, I4, I5, I6, I7 or I8 ignition coil with
igniter connector.
(b) Turn the ignition switch to ON.
CHECK:
Measure the voltage between terminals the E6 and E8 ECM
connectors when the engine is cranked.
OK:
Standard:
Tester ConnectionSpecified Condition
IGT1 (E8±8) ± E1 (E6±1)4.5 V or more
IGT2 (E8±15) ± E1 (E6±1)4.5 V or more
IGT3 (E8±11) ± E1 (E6±1)4.5 V or more
IGT4 (E8±10) ± E1 (E6±1)4.5 V or more
IGT5 (E8±13) ± E1 (E6±1)4.5 V or more
IGT6 (E8±12) ± E1 (E6±1)4.5 V or more
IGT7 (E8±14) ± E1 (E6±1)4.5 V or more
IGT8 (E8±9) ± E1 (E6±1)4.5 V or more
NG Replace ECM (See page SF±80).
OK
Page 426 of 4323
A21025
Wire Harness Side:
I1
I2
I3I4
I5I6
I7I8Ignition Coil with
Igniter Connector
DI±232
± DIAGNOSTICSENGINE
426 Author: Date:
2005 SEQUOIA (RM1146U)
7 Check ignition coil with igniter power source circuit.
PREPARATION:
(a) Disconnect the I1, I2, I3, I4, I5, I6, I7 or I8 ignition coil with
igniter connector.
(b) Turn the ignition switch to ON.
CHECK:
Measure the voltage between the terminal of the wire harness
side connector and body ground.
OK:
Standard:
Tester ConnectionSpecified Condition
I1±1 ± Body ground
I2±1 ± Body ground
I3±1 ± Body ground
I4±1 ± Body ground9t 14VI5±1 ± Body ground9 to 14 V
I6±1 ± Body ground
I7±1 ± Body ground
I8±1 ± Body ground
OK Repair ignition coil with igniter.
NG
Page 427 of 4323

A21025
Wire Harness Side:
I1
I2
I3I4
I5I6
I7I8Ignition Coil with Igniter
A21378
Wire Harness Side:
I18
Ignition SwitchIG2
± DIAGNOSTICSENGINE
DI±233
427 Author: Date:
2005 SEQUOIA (RM1146U)
8 Check for open and short in harness and connector between ignition switch and
ignition coil with igniter.
PREPARATION:
(a) Disconnect the I1, 2, I3, I4, I5, I6, I7 or I8 ignition coil with
igniter connector.
(b) Disconnect the I18 ignition switch connector.
CHECK:
Measure the resistance between the wire harness side connec-
tors.
OK:
Standard:
Tester ConnectionSpecified Condition
Ignition coil (I1±1) ± IG2 (I18±6)Below 1 W
Ignition coil (I2±1) ± IG2 (I18±6)Below 1 W
Ignition coil (I3±1) ± IG2 (I18±6)Below 1 W
Ignition coil (I4±1) ± IG2 (I18±6)Below 1 W
Ignition coil (I5±1) ± IG2 (I18±6)Below 1 W
Ignition coil (I6±1) ± IG2 (I18±6)Below 1 W
Ignition coil (I7±1) ± IG2 (I18±6)Below 1 W
Ignition coil (I8±1) ± IG2 (I18±6)Below 1 W
Ignition coil (I1±1) or IG2 (I18±6) ±
Body ground10 kW or higher
Ignition coil (I2±1) or IG2 (I18±6) ±
Body ground10 kW or higher
Ignition coil (I3±1) or IG2 (I18±6) ±
Body ground10 kW or higher
Ignition coil (I4±1) or IG2 (I18±6) ±
Body ground10 kW or higher
Ignition coil (I5±1) or IG2 (I18±6) ±
Body ground10 kW or higher
Ignition coil (I6±1) or IG2 (I18±6) ±
Body ground10 kW or higher
Ignition coil (I7±1) or IG2 (I18±6) ±
Body ground10 kW or higher
Ignition coil (I8±1) or IG2 (I18±6) ±
Body ground10 kW or higher
NG Repair or replace harness or connector.
OK
Replace ignition coil with igniter.
Page 428 of 4323

B17432
Air PumpPressure
Sensor
Air
Air Injection
Driver (AID)
Air Switching Valve
(ASV)(EASV)Air Switching Valve No.2
(ASV No.2)(ASV1)VSV for Air Injection
Control
ECMEngine Coolant
Temp. Sensor
Mass Air Flow
Meter
Intake Air Temp.
Sensor To Bank 2To Bank1
Air Switching Valve No.2
(ASV No.2)(ASV2)
DI±234
± DIAGNOSTICSENGINE
428 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P0412 Secondary Air Injection System Air Switch-
ing Valve ºAº Circuit
CIRCUIT DESCRIPTION
The secondary air injection system pumps air to the exhaust port to accelerate the activation of the catalyst.
The secondary air injection system consists of the ECM, air pump, Air Switching Valve (ASV) (EASV), Air
Switching Valve No.2 (ASV No.2) (ASV1, 2), pressure sensor and air injection driver (AID). The Air Switching
Valve (ASV)(EASV) is an electromagnetic type and Air Switching Valve No.2 (ASV No.2)(ASV1,2) is a vacu-
um type.
The secondary air injection system pumps pressurized air to the exhaust port by the air pump through the
ASV and ASV No.2. The ASV assists the ASV No.2. The ASV No.2 also controls air supply.
The ECM sends signals to the AID, and then the AID operates the air pump and ASV. The pressure sensor
detects pressure and exhaust pulsation in the system when the system operates and when it does not oper-
ate, and sends the data to the ECM.
DTC No.DTC Detection ConditionTrouble Area
P0412
All of the following conditions are met when engine is idling just
after cold start
(1 trip detection logic):
(a) Air injection system does not operate (Air pump OFF and all
ASVs OFF)
(b) Air injection driver diagnostic signal duty is 40%.Open in air switching valve drive circuit
Short between air switching valve circuit and +B circuit
Air injection driver
Air switching valve
ECM
P0412
All of the following conditions are met when engine is idling just
after cold start
(1 trip detection logic):
(a) Air injection system operates (Air pump ON and all ASVs
ON)
(b) Air injection driver diagnostic signal duty is 40%.
Short between air switching valve circuit and body ground
Air injection driver
Air switching valve
ECM
DIDMV±01
Page 429 of 4323

± DIAGNOSTICSENGINE
DI±235
429 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR DESCRIPTION
The air injection driver (AID) detects an open or short in the circuit according to the voltage of the air pump
terminal (VP) and electromagnetic air switching valve terminal (VV), and sends a signal as diagnostic in-
formation to the ECM.
The AID outputs the air switching valve terminal malfunction signal to the ECM if: 1) VV terminal voltage is
low despite the AID receiving the command signal from the ECM to drive the air switching valve terminal or
2) VV terminal voltage is high despite the AID not receiving the command signal from the ECM.
The ECM stores the DTC based on the diagnostic signal from the AID and illuminates the MIL.
MONITOR STRATEGY
Related DTCsP0412Air switching valve circuit malfunction (Second-
ary air injection system)
Required sensors/componentsAir injection driver, Air switching valve
Frequency of operationContinuous
Duration3 sec.
MIL operationImmediate
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever this DTC is
not presentSee page DI±18
Case 1:
Air pumpOperating
Air switching valveOperating
Battery voltage8 V±
Ignition switchON
StarterOFF
Case 2:
Air pumpNot operating
Air switching valveNot operating
Battery voltage8 V±
Ignition switchON
StarterOFF
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
Case 1, 2:
Diagnostic signal duty ratio from air injection driver31 to 48 %
COMPONENT OPERATING RANGE
ParameterStandard Value
Diagnostic signal duty ratio from air injection driver
70 to 90% when secondary air injection system operating
and
0% when secondary air injection system not operating
Page 430 of 4323
A23551
Engine Room J/BECM
E4
E4
E4
E4 B±W
IA4
IA4
IA4
IA4
IA4
EB4 ED2
ED2B±W
2H
2A68
EFI Relay
2 1
2F
1 W±B
J5
J/C A
ED
Battery Air Pump Air Switching Valve Air Injection Driver
A43 A46A415
G±RG±R
J2
J/C
A
A EFI No.2 EFI No.1
3 52
2D1
B
4F10
FL Block
5B L
A401
EN B B
B 1
12
2 W
W±L W±L
W
34 2
6 A40
A41A41
A41
A41
A411 2 43
1
8
EBW±BW±B W±B
BATT
VP
VV
E SIP
DI SIV+B
R±W
R±W 8
3
9 G±W G±W
GR±L GR±L4
25
13
AIDAIRPAIRV
A/PUMP
2MREL DI±236
± DIAGNOSTICSENGINE
430 Author: Date:
2005 SEQUOIA (RM1146U)
WIRING DIAGRAM
Page 431 of 4323

B17411
ECM Connector
E1AIDI
A16555
AIR INJ CHECK
AIR PUMP............................ON
EASV ............................OPEN
ASV1. .............................OPEN
ASV2...............................OPEN
A/F BANK1.......................19.05
A/F BANK2.......................19.05
PRESSURE....................17 kPa
PULSATION..............25.39 kPa
AI STATUS...........................OK
Remaining Time 05 sec.
Press [EXIT] to quit
Example: 80% Duty Signal5 V/DIV.
GND
20 ms/DIV.
± DIAGNOSTICSENGINE
DI±237
431 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
HINT:
The diagnostic information output from the AID can be confirmed by connecting an oscilloscope to the diag-
nostic information terminal of the AID. It narrows the trouble area to read the waveform on the oscilloscope
when performing the AI system intrusive operation function provided in the SYSTEM CHECK.
(1) Start the engine and warm it up.
(2) Turn the ignition switch to OFF.
(3) Connect a hand±held tester to the DLC3.
(4) Connect an oscilloscope probe to the AIDI terminal
of the ECM.
(5) Start the engine and turn the tester ON.
(6) On the tester, select the following menu items:
DIAGNOSIS / ENHANCED OBD II / SYSTEM
CHECK / AIR INJ CHECK / MANUAL OPERATION
/ OPERATION 1 and 2.
HINT:
OPERATION 1: AP: OFF, EASV:CLOSE, ASV1:CLOSE,
ASV2:CLOSE
OPERATION 2: AP: ON, EASV:OPEN, ASV1:OPEN,
ASV2:OPEN
(7) Monitor the voltage output of the AID (duty ratio sig-
nal).
Oscilloscope range:
ItemsContents
TerminalsCH1: AIDI ± E1
Equipment Settings5 V/Division, 20 to 40 ms/Division
ConditionsIdling
NOTICE:
This AIR INJECTION CHECK only allows technicians to operate the AI system for 5 seconds.
Furthermore, the check can be performed 4 times a trip. If the test is repeated, intervals of at
least 30 seconds are required between checks.
While the AI system operation using the hand±held tester is prohibited, the tester displays the
prohibition (WAIT or ERROR). If the ERROR (AI STATUS NG) is displayed on the tester, stop the
engine for 10 minutes and then try again.
Performing the AIR INJ CHECK over and over again may cause the damage in the secondary
air injection system. If necessary, put an interval of several minutes between tests to prevent
overheating the system.
Page 432 of 4323

A23464
AID Diagnostic Signal WaveformsECM
CommandsDTCs
Suspected Trouble Areas
(ECM Output)
100 % Duty ratio
+B
Almost Battery Voltage
GND
0 % Duty ratio
+B
Fixed at Low Voltage
GND
20 % Duty ratio
20 %
+B
GND
40 % Duty ratio
40 %
+B
GND
80 % Duty ratio
80 %
+B
GND
Excluding above
(excluding 0, 20, 40, 80, 100 % duty)
Air Pump: ON
Air Pump: OFF
ASV: ON
ASV: OFF
AI System: OFF
(Air pump OFF,
ASV OFF)
AI System: ON
(Air pump ON,
ASV ON)
P1613
P0418
P0418
P0412
P0412
P1613
P1613
Air Injection Control Driver (AID)
Open in AID+B circuit (AID power source)
Open or short in air pump or Air Switching Valve
AID
ECM
Open in air pump drive circuit (AID±Pump) ,Harness & connector (AID±Pump)
Air PumpAIDECM
Short between air pump drive circuit and body ground
AID
ECM
Harness & connector (AID±Pump)Air Pump
Open in ASV drive circuit (AID±ASV),Harness & connector (AID±ASV)
ASVAIDECM
Short between ASV drive circuit and body ground
Harness & connector (AID±ASV)
AID
ECM
ECM
Normal
AID
AID
or short between air pump drive circuit and +B
or short between ASV drive circuit and +B
'
'
ASV
±
AI System: OFF
(Air pump OFF,
ASV OFF) AI System: ON
(Air pump ON,
ASV ON)
Normal Any Air Injection
(AI) System op-
eration
P1613
Open in AID ground circuit
Short between +B circuit and diagnostic signal circuit
Short between diagnostic signal circuit and body
(ASV) command signal circuit (ECM±AID)
ground
Open in AID ground circuit
Open in diagnostic signal circuit
DI±238
± DIAGNOSTICSENGINE
432 Author: Date:
2005 SEQUOIA (RM1146U)