Page 433 of 4323

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
Page 434 of 4323
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).
Page 435 of 4323
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.
Page 436 of 4323

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
Page 437 of 4323
± 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.
Page 438 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. DI±244
± DIAGNOSTICSENGINE
438 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 search to read the waveform on the oscillo-
scope 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 SYSTEM.
(7) 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
(8) 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 (AI STATUS NG) or ERROR. At this time 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 439 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
± DIAGNOSTICSENGINE
DI±245
439 Author: Date:
2005 SEQUOIA (RM1146U)
Page 440 of 4323

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