2001 TOYOTA SEQUOIA engine

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.

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)

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

A23498
Component Side:
Air Pump Connector
Front View
A43
B17438
Wire Harness Side:
Air Pump Connector
A43
± DIAGNOSTICSENGINE
DI±247
441 Author: Date:
2005 SEQUOIA (RM1146U)
2 Check air pump resistance.
(a) Remove the intake manifold (see page EM±36).
(b) Disconnect the air pump connector.
(c) Measure the resistance of the air pump.
Standard:
Tester ConnectionsSpecified Conditions
A43±1 ± A43±20.4 to 1.0 W
NG Replace air pump assembly.
OK
3 Check for open in harness and connector between air pump and body ground.
PREPARATION:
(a) Remove the intake manifold (see page EM±36).
(b) Disconnect the A43 air pump connector.
CHECK:
Measure the resistance between the wire harness side connec-
tors and body ground.
OK:
Standard:
Tester ConnectionSpecified Condition
A43±1 ± Body groundBelow 1 W
NG Repair or replace harness or connector.
OK
Check for intermittent problems
(See page DI±11).

B17443
Wire Harness Side:
Air Injection Driver Connector
A40
B17438
Wire Harness Side:
Air Pump Connector
A43
DI±248
± DIAGNOSTICSENGINE
442 Author: Date:
2005 SEQUOIA (RM1146U)
4 Check for open and short in harness and connector between air injection driver
and air pump.
PREPARATION:
(a) Remove the intake manifold (see page EM±36).
(b) Disconnect the A40 air injection driver connector.
(c) Disconnect the A43 air pump connector.
CHECK:
Measure the resistance between the wire harness side connec-
tors.
OK:
Standard:
Tester ConnectionSpecified Condition
VP (A40±2) ± A43±2Below 1 W
VP (A40±2) or A43±2 ±
Body ground10 kW or higher
NG Repair or replace harness or connector.
OK
Replace air injection driver.

± DIAGNOSTICSENGINE
DI±249
443 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P0420 Catalyst System Efficiency Below Threshold
(Bank 1)
DTC P0430 Catalyst System Efficiency Below Threshold
(Bank 2)
MONITOR DESCRIPTION
The ECM uses the two sensors, mounted in front of and behind the Three±way Catalytic Converter (TWC),
to monitor its efficiency.
The first sensor, the Air±Fuel Ratio (A/F) sensor (sensor 1), sends pre±catalyst information to the ECM. The
second sensor, the Heated Oxygen (HO2) sensor (sensor 2), sends post±catalyst information to the ECM.
The ECM compares the information transmitted by these two sensors to determine the efficiency of the TWC
performance and its ability to store oxygen.
When the TWC is functioning properly, the variation in the oxygen concentration in the exhaust gas, after
it has passed through the TWC, is small. In this condition, the voltage output of sensor 2 slowly alternates
between the rich and lean signal voltages (shown in the illustration below). As the TWC performance efficien-
cy deteriorates, its oxygen storage capacity decreases, and the variation in the oxygen concentration in the
exhaust gas increases. As a result, the sensor voltage output fluctuates frequently.
While the catalyst monitor is running, the ECM measures the signal lengths of both sensors 1 and 2, and
calculates the ratio of the signal lengths to determine the extent of the TWC deterioration. If the deterioration
level exceeds the preset threshold, the ECM interprets this as the TWC malfunction. The ECM then illumi-
nates the MIL and sets the DTC.
DTC No.DTC Detecting ConditionTrouble Area
P0420
P0430OSC value smaller than standard value under active air±fuel
ratio control (2 trip detection logic)
Gas leakage on exhaust system
A/F sensor (Bank 1, 2 sensor 1)
Heated oxygen sensor (bank 1, 2 sensor 2)
Three±way catalytic converter
HINT:
Bank 1 refers to the bank that includes cylinder No.1.
Bank 2 refers to the bank that does not include cylinder No.1.
Sensor 1 refers to the sensor mounted in front of the Three±Way Catalytic Converter (TWC) and lo-
cated near the engine assembly.
Sensor 2 refers to the sensor mounted behind the TWC and located far from the engine assembly.
DID87±01

DI±250
± DIAGNOSTICSENGINE
444 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR STRATEGY
RltdDTCP0420Bank 1 catalyst is deterioratedRelated DTCsP0430Bank 2 catalyst is deteriorated
Main sensors/componentsFront and rear heated oxygen sensor
Required sensors/componentsRelated sensors/components
Mass air flow meter, Engine coolant temperature
sensor, Engine speed sensor, Intake air tempera-
ture sensor
Frequency of operationOnce per driving cycle
Duration20 sec.
MIL operation2 driving cycles
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever these
DTCs are not presentSee page DI±18
Battery voltage11 V±
Intake air temperature±10C (14F)±
Engine coolant temperature75°C (167°F)±
Atmospheric pressure coefficient0.75±
IdleOFF
Engine RPM±3,200 rpm
A/F sensorActivated
Fuel system statusClosed loop
Engine load10 to 70 %
All of the following conditions are metCondition 1, 2 and 3
1. MAF6to 75 g/sec
2. Front catalyst temperature (estimated)620to 830C (1,148 to 1,526F)
3. Rear catalyst temperature (estimated)410 to 830C (770 to 1,526F)
Rear HO2S monitorCompleted
Shift position4th±
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
Oxygen storage capacity (OSC) of catalystLess than 0.16

A23541
At least 3 minutes
2 seconds
Check
2 seconds
Engine Speed
3,000 rpm
2,000 rpm
Idling
Ignition Switch OFF(a)(b)(c) (d)
Time
Warming up(d)
± DIAGNOSTICSENGINE
DI±251
445 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR RESULT
Refer to page DI±26 for detailed information.
The test value and test limit information are described as shown in the following table. Check the monitor
result and test values after performing the monitor drive pattern (refer to ºConfirmation Monitorº).
MID (Monitor Identification Data) is assigned to each emissions±related component.
TID (Test Identification Data) is assigned to each test value.
Scaling is used to calculate the test value indicated on generic tools.
Catalyst bank 1 ± Active A/F control method
MIDTIDScalingDescription of Test ValueMinimum Test LimitMaximum Test Limit
$21$A9Multiply by 0.0003
(no dimension)Oxygen storage capacity of catalystMinimum test limit for catalystMaximum test limit for catalyst
Catalyst bank 2 ± Active A/F control method
MIDTIDScalingDescription of Test ValueMinimum Test LimitMaximum Test Limit
$22$A9Multiply by 0.0003
(no dimension)Oxygen storage capacity of catalystMinimum test limit for catalystMaximum test limit for catalyst
WAVEFORMS OF AIR±FUEL RATIO (A/F) AND HEATED OXYGEN (HO2) SEN-
SORS
HINT:
Perform the operation with the engine speeds and time durations described below prior to check the wave-
forms of the A/F and HO2 sensors. This is in order to activate the sensors sufficiently to obtain the appropri-
ate inspection results.
(a) Connect the hand±held tester to the DLC3.
(b) Start the engine and warm it up with all the accessories switched OFF, until the engine coolant temper-
ature stabilizes.
(c) Run the engine at an engine speed of between 2,500 rpm and 3,000 rpm for at least 3 minutes.
(d) After confirming that the waveform of the heated oxygen sensor (bank 1, 2 sensor 1 (HA1A, HA2A)),
oscillate around 0.5 V during feedback to the ECM, check the waveform of the heated oxygen sensor
(bank 1, 2 sensor 2 (OX1B, OX2B)).