2001 TOYOTA SEQUOIA Page 18

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

± 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

B17440
A46
Air Switching Valve Connector Wire Harness Side:
± DIAGNOSTICSENGINE
DI±239
433 Author: Date:
2005 SEQUOIA (RM1146U)
HINT:

Using the AIR INJ CHECK operation of the SYSTEM CHECK provided in the hand±held tester func-
tion, conditions for air±fuel ratio and pressure in the secondary air injection system passage can be
checked while the secondary air injection system operating. It helps technicians to troubleshoot the
system when it malfunctioning.

Read freeze frame data using a hand±held tester. Freeze frame data record the engine condition when
malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle
was moving or stationary, if the engine was warmed up or not, if the air±fuel ratio was lean or rich, and
other data, from the time the malfunction occurred.
1 Check voltage between terminal 1 of air switching valve connector and body
ground.
PREPARATION:
(a) Remove the intake manifold (see page EM±36).
(b) Disconnect the A46 air switching valve connector.
(c) Connect the hand±held tester to the DLC3.
(d) Turn the ignition switch ON and turn the tester ON.
CHECK:
(a) When the air switching valve is operated using the hand±
held tester, measure voltage between terminal A46±1 of
the air switching valve connector and body ground.
(b) Select the following menu items: DIAGNOSIS/EN-
HANCED OBD II/SYSTEM CHECK/ AIR INJ CHECK/
MANUAL OPERATION/OPERATION 1 and 4
HINT:
OPERATION 1: AP:OFF, EASV:CLOSE, ASV1:CLOSE,
ASV2:CLOSE
OPERATION 4: AP:OFF, EASV:OPEN, ASV1:CLOSE,
ASV2:CLOSE
NOTICE:
This test only allows technicians to operate the AI system
for 5 seconds. Furthermore, the test can be performed 4
times a trip. If the test is repeated, intervals of at least 30
seconds are required between tests.
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..
OK:
Standard:
Tester operationTester ConnectionSpecified Condition
Operation 4A46±1 ± Body ground10 V or more
Operation 1A46±1 ± Body groundBelow 1.0 V
NG Go to step 4.
OK

A23465
Component Side:
ASV Connector
Front View
A46
B17440
A46
Air Switching Valve Connector Wire Harness Side:
DI±240
± DIAGNOSTICSENGINE
434 Author: Date:
2005 SEQUOIA (RM1146U)
2 Check air switching valve.
(a) Remove the intake manifold (see page EM±36).
(b) Disconnect the ASV connector.
(c) Measure the resistance of the ASV.
Standard:
Tester ConnectionsSpecified Conditions
A46±1 ± A46±24.5 to 5.5 W
NG Replace air switching valve.
OK
3 Check for open in harness and connector between air switching valve and body
ground.
PREPARATION:
(a) Remove the intake manifold (see page EM±36).
(b) Disconnect the A46 air switching valve connector.
CHECK:
Measure the resistance between the wire harness side connec-
tors and body ground.
OK:
Standard:
Tester ConnectionSpecified Condition
A46±2 ± Body groundBelow 1 W
NG Repair or replace harness or connector.
OK
Check for intermittent problems
(See page DI±11).

B17444
Wire Harness Side:
Air Injection Driver Connector
A41
VV
B17440
A46
Air Switching Valve Connector Wire Harness Side:
± DIAGNOSTICSENGINE
DI±241
435 Author: Date:
2005 SEQUOIA (RM1146U)
4 Check for open and short in harness and connector between air injection driver
and air switching valve.
PREPARATION:
(a) Remove the intake manifold (see page EM±36).
(b) Disconnect the A41 air injection driver connector.
(c) Disconnect the A46 air switching valve connector.
CHECK:
Measure the resistance between the wire harness side connec-
tors.
OK:
Standard:
Tester ConnectionSpecified Condition
VV (A41±6) ± A46±1Below 1 W
VV (A41±6) or A46±1 ±
Body ground10 kW or higher
NG Repair or replace harness or connector.
OK
Replace air injection driver.

DI±242
± DIAGNOSTICSENGINE
436 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P0418 Air Injection System Air Pump Malfunction
CIRCUIT DESCRIPTION
Refer to DTC P0412 on page DI±234.
DTC No.DTC Detection ConditionTrouble Area
P0418
All of the following conditions are met, when idling just after
cold start. (1 trip detection logic):
(a) Air injection system not operate
(b) Air injection driver outputs air pump malfunction signal (20%
duty signal)
Open in air pump drive circuit

Short between air pump circuit and +B circuit

Air injection driver

ECM
P0418
All of the following conditions are met, when idling just after
cold start.
(1 trip detection logic):
(a) Air injection system operates
(b) Air injection driver outputs air pump malfunction signal (20%
duty signal)

Short between air pump circuit and body ground

Air injection driver

ECM
MONITOR DESCRIPTION
Air Injection Driver (AID) detects an open or short in the air pump and Air Switching Valve (ASV) circuit ac-
cording to the terminal voltage and sends a signal as diagnostic information to the ECM.
When the air injection system operation is required while the engine is warming up, the ECM transmits com-
mand signals to the AID to drive the air pump and ASV.
The AID inputs the command signal from ECM if: 1) VP terminal voltage is low despite the AID inputting the
command signal from the ECM to drive the ASV or 2) VP terminal voltage is high despite the AID not inputting
the command signal from the ECM.
The ECM sets the DTC based on the diagnostic information from the AID.
MONITOR STRATEGY
Related DTCsP0418Air pump range check
Required sensors/componentsAir injection driver, Air pump
Frequency of operationContinuous
Duration3 sec.
MIL operationImmediate
Sequence of operationNone
DIDMW±01

± DIAGNOSTICSENGINE
DI±243
437 Author: Date:
2005 SEQUOIA (RM1146U)
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 driver11 to 29 %
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
WIRING DIAGRAM
Refer to DTC P0412 on page DI±234.

B17438
Wire Harness Side:
Air Pump Connector
A43
DI±246
± DIAGNOSTICSENGINE
440 Author: Date:
2005 SEQUOIA (RM1146U)
HINT:

Using the AIR INJ CHECK operation of the SYSTEM CHECK provided in the hand±held tester func-
tion, conditions for air±fuel ratio and pressure in the secondary air injection system passage can be
checked while the secondary air injection system operating. It helps technicians to troubleshoot the
system when it malfunctioning.

Read freeze frame data using a hand±held tester. Freeze frame data record the engine condition when
malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle
was moving or stationary, if the engine was warmed up or not, if the air±fuel ratio was lean or rich, and
other data, from the time the malfunction occurred.
1 Check voltage between terminal 2 of air pump and body ground.
PREPARATION:
(a) Remove the intake manifold (see page EM±36).
(b) Disconnect the A43 air pump connector.
(c) Connect the hand±held tester to the DLC3.
(d) Turn the ignition switch ON and turn the tester ON.
CHECK:
(a) When the air pump is operated using the hand±held tes-
ter, measure the voltage between terminal A43±2 of the
air injection driver connector and body ground.
(b) Select the following menu items: DIAGNOSIS/EN-
HANCED OBD II/SYSTEM CHECK/ AIR INJ CHECK/
MANUAL OPERATION/OPERATION 1 and 3
HINT:
OPERATION 1: AP:OFF, EASV:CLOSE, ASV1:CLOSE,
ASV2:CLOSE
OPERATION 3: AP:ON, EASV:OPEN, ASV1:OPEN,
ASV2:OPEN
NOTICE:
This test only allows technicians to operate the AI system
for 5 seconds. Furthermore, the test can be performed 4
times a trip. If the test is repeated, intervals of at least 30
seconds are required between tests.
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..
OK:
Standard:
Tester operationTester ConnectionSpecified Condition
Operation 3A43±2 ± Body ground10 V or more
Operation 1A43±2 ± Body groundBelow 1.0 V
NG Go to step 4.
OK