TOYOTA SEQUOIA 2001 Service Repair Manual

A21226
Wire Harness Side:
Mass Air Flow Meter Connector
M1
E2GVG
B17412
E8ECM Connector
E2G
VG
± DIAGNOSTICSENGINE
DI±107
301 Author: Date:
2005 SEQUOIA (RM1146U)
4 Check for open and short in harness and connector between mass air flow meter
and ECM.
PREPARATION:
(a) Disconnect the M1 mass air flow meter connector.
(b) Disconnect the E8 ECM connector.
CHECK:
Check the resistance between the wire harness side connec-
tors.
OK:
Standard:
Tester ConnectionSpecified Condition
VG (M1±3) ± VG (E8±30)Below 1 W
E2G (M1±2) ± E2G (E8±29)Below 1 W
VG (M1±3) or VG (E8±30) ±
Body ground10 kW or higher
NG Repair or replace harness or connector.
OK
Replace mass air flow meter.

A21375
Engine Room J/B:
EFI
No. 2 Fuse
A21226
Wire Harness Side:
Mass Air Flow Meter Connector
M1
+B
A21376
Engine Room J/B:
EFI Relay
DI±108
± DIAGNOSTICSENGINE
302 Author: Date:
2005 SEQUOIA (RM1146U)
5 Check for open and short in harness and connector between mass air flow meter
and EFI relay.
PREPARATION:
Remove the EFI No. 2 fuse from the engine room J/B.
CHECK:
Check the resistance in the EFI No. 2 fuse.
OK:
Standard:
Below 1 W
PREPARATION:
(a) Install the EFI No. 2 fuse.
(b) Disconnect the M1 mass air flow meter connector.
(c) Remove the EFI relay from the engine room J/B.
CHECK:
Check the resistance between the wire harness side connec-
tors.
OK:
Standard:
Tester ConnectionSpecified Condition
+B (M1±1) ± Engine Room J/B (EFI
relay terminal 1)Below 1 W
+B (M1±1) or Engine room J/B (EFI relay
terminal 1) ± Body ground10 kW or higher
NG Repair or replace harness or connector.
OK
Check ECM power source circuit
(See page DI±493).

B17412E2G E8
ECM Connector
A21226
Wire Harness Side:
Mass Air Flow Meter Connector
M1
VGE2G
B17412
E8ECM Connector
E2G
VG
± DIAGNOSTICSENGINE
DI±109
303 Author: Date:
2005 SEQUOIA (RM1146U)
6 Check continuity between terminal E2G of ECM connector and body ground.
CHECK:
Check the resistance between terminal of the E8 ECM connec-
tor and body ground.
OK:
Standard:
Tester ConnectionSpecified Condition
E2G (E8±29) ± Body groundBelow 1 W
NG Replace ECM (See page SF±80).
OK
7 Check for open in harness and connector between mass air flow meter and ECM.
PREPARATION:
(a) Disconnect the M1 mass air flow meter connector.
(b) Disconnect the E8 ECM connector.
CHECK:
Check the resistance between the wire harness side connec-
tors.
OK:
Standard:
Tester ConnectionSpecified Condition
VG (M1±3) ± VG (E8±30)Below 1 W
E2G (M1±2) ± E2G (E8±29)Below 1 W
VG (M1±3) or VG (E8±30) ±
Body ground10 kW or higher
E2G (M1±2) or E2G (E8±29) ±
Body ground10 kW or higher
NG Repair or replace harness or connector.
OK
Replace mass air flow meter.

DI±110
± DIAGNOSTICSENGINE
304 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P0101 Mass or Volume Air Flow Circuit Range/
Performance Problem
CIRCUIT DESCRIPTION
Refer to DTC P0100, P0102 and P0103 on page DI±102.
DTC No.DTC Detecting ConditionTrouble Area
P0101
After engine is warmed up, conditions (a), (b), (c) and (d) con-
tinue for more than 10 seconds:
(2 trip detection logic)
(a) Throttle valve fully closed
(b) Voltage output of the mass air flow meter is more than 2.2
V.
(c) Engine coolant temperature is more than 70 °C (158 °F).
(d) Engine speed is less than 2,000 rpm.

Mass air flow meter
Conditions (a), (b) and (c) continue for more than 10 seconds
at engine speed: (2 trip detection logic)
(a) Engine speed is more than 300 rpm.
(b) Voltage output of the mass air flow meter is less than 1.0 V.
MONITOR DESCRIPTION
The MAF (Mass Air Flow) meter helps the ECM calculate the amount of air flowing through the throttle valve.
The ECM uses this information to determine the fuel injection time and provide a proper air fuel ratio. Inside
the MAF meter, there is a heated platinum wire exposed to the flow of intake air. By applying a specific current
to the wire, the ECM heats this wire to a given temperature. The flow of incoming air cools the wire and an
internal thermistor, affecting their resistance. To maintain a constant current value, the ECM varies the volt-
age applied to these components in the MAF meter. The voltage level is proportional to the air flow through
the MAF meter. The ECM interprets this voltage as the intake air amount. If there is a defect in the MAF meter
or an open or short circuit, the voltage level will deviate outside the normal operating range. The ECM inter-
prets this deviation as a defect in the MAF meter and sets a DTC.
Example:
If the voltage is more than 2.2 V at idle or less than 1.0 V at idle OFF, the ECM interprets this as a defect
in the MAF meter and sets a DTC.
MONITOR STRATEGY
RltdDTCP0101Mass air flow meter rationality (Low voltage)Related DTCsP0101Mass air flow meter rationality (High voltage)
Main sensors/componentsMass air flow meter
Required sensors/componentsRelated sensors/componentsEngine speed sensor, Engine coolant tempera-
ture sensor, Throttle position sensor
Frequency of operationContinuous
Duration10 sec.
MIL operation2 driving cycles
Sequence of operationNone
DI3HM±13

± DIAGNOSTICSENGINE
DI±111
305 Author: Date:
2005 SEQUOIA (RM1146U)
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever this DTC is
not presentSee page DI±18
High voltage:
Engine speed±2,000 rpm
MAF meter voltage±4.9 V
Engine coolant temperature70C (158F)±
Low voltage:
Engine speed300 rpm±
MAF meter voltage0.2 V±
Fuel cutOFF
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
Mass air flow meter voltage (High voltage)More than 2.2 V (varies with throttle position sensor voltage)
Mass air flow meter voltage (Low voltage)Less than 1.0 V (varies with throttle position sensor voltage)

DI±112
± DIAGNOSTICSENGINE
306 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
HINT:
Read freeze frame data using the hand-held tester. Freeze frame data records the engine conditions when
a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was
running or stopped, if the engine was warmed up or not, if the air±fuel ratio was lean or rich, as well as other
data from the time when a malfunction occurred.
1 Are there any other codes (besides DTC P0101) being output?
PREPARATION:
(a) Connect the hand±held tester to the DLC3.
(b) Turn the ignition switch ON and push the hand±held tester main switch ON.
(c) When using hand±held tester, enter the following menu: DIAGNOSIS/ENHANCED OBD II/DTC INFO/
CURRENT CODES.
CHECK:
Read the DTC using the hand±held tester.
RESULT:
Display (DTC output)Proceed to
ºP0101º and other DTCsA
Only P0101B
HINT:
If any other codes besides P0101 are output, perform the troubleshooting for those codes first.
B Replace mass air flow meter.
A
Go to relevant DTC chart (See page DI±58).

± 20 0 20 40 60 80 100
(± 4) 32 68 104 140 176 212 30
20
10
5
3
2
1
0.5
0.3
0.2
0.1
A21047
Acceptable (Fig.1)
Resistance KW
Temp. C (F)
± DIAGNOSTICSENGINE
DI±113
307 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P0110 Intake Air Temperature Circuit
DTC P0112 Intake Air Temperature Circuit Low Input
DTC P0113 Intake Air Temperature Circuit High Input
CIRCUIT DESCRIPTION
The intake air temperature (IAT) sensor, mounted on the mass
air flow (MAF) meter, monitors the intake air temperature. The
IAT sensor has a thermistor that varies its resistance depending
on the temperature of the intake air. When the air temperature
is low, the resistance in the thermistor increases. When the tem-
perature is high, the resistance drops. The resistance varies as
voltage changes to the ECM terminal.
(See Fig. 1).
The intake air temperature sensor is connected to the ECM
(See below ). The 5 V power source voltage in the ECM is ap-
plied to the intake air temperature sensor from terminal THA
(THAR) via resistor R.
That is, the resistor R and the intake air temperature sensor are
connected in series. When the resistance value of the intake air
temperature sensor changes in accordance with changes in the
intake air temperature, the voltage at terminal THA (THAR) also
changes. Based on this signal, the ECM increases the fuel in-
jection volume to improve the driveability during cold engine op-
eration.
DTC No.Proceed toDTC Detection ConditionTrouble Area
P0110Step 1
Open or short in intake air
temperature sensor circuit for
0.5 sec.

Open or short in intake air temperature sensor circuit
P0112Step 4Short in intake air tempera-
ture sensor circuit for 0.5 sec.

Open or short in intake air temperature sensor circuit

Intake air temperature sensor (built in mass air flow meter)

ECM
P0113Step 2Open in intake air tempera-
ture sensor circuit for 0.5 sec.
ECM
HINT:
After confirming DTC ºP0110, P0112 or P0113º, use the hand±held tester to confirm the intake air tempera-
ture in the ºDIAGNOSIS / ENHANCED OBD II / DATA LIST / ALLº.
Temperature DisplayedMalfunction
±40°C (±40°F)Open circuit
140°C (284°F) or moreShort circuit
DI3HN±13

DI±114
± DIAGNOSTICSENGINE
308 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR DESCRIPTION
The ECM monitors the sensor voltage and uses this value to calculate the intake air temperature. When the
sensor output voltage deviates from the normal operating range, the ECM interprets this as a fault in the IAT
(Intake Air Temperature) sensor and sets a DTC.
Example:
When the sensor voltage output is equal to ±40C (±40F), or more than 140C (284F).
MONITOR STRATEGY
P0110Intake air temperature sensor range check
(Fluttering)
Related DTCsP0112Intake air temperature sensor range check
(Low resistance)
P0113Intake air temperature sensor range check
(High resistance)
Required sensors/componentsIntake air temperature sensor
Frequency of operationContinuous
Duration0.5 sec.
MIL operationImmediate
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
The monitor will run whenever these
DTCs are not presentSee page DI±18
The typical enabling condition is not avail-
able±
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
P0110:
Intake air temperature sensor resistance
(Intake air temperature)Less than 98.5 W, or more than 156 kW
(More than 140C (284F), or less than ±40C (±40F)
P0112:
Intake air temperature sensor resistance
(Intake air temperature)Less than 98.5 W
(More than 140C (284F))
P0113:
Intake air temperature sensor resistance
(Intake air temperature)More than 156 kW
(Less than ±40C (±40F))
COMPONENT OPERATING RANGE
ParameterStandard Value
Intake air temperature sensor resistance98.5 W (140C (284F)) to 156 kW (±40C (±40F))

A15651
ECM
Intake Air Temp. Sensor
(Built into Mass Air Flow Meter)
54 Y±G5 V
THA 22R
E8
E8 G±W28
E2
E1 M1
THA
E2
± DIAGNOSTICSENGINE
DI±115
309 Author: Date:
2005 SEQUOIA (RM1146U)
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:

If DTCs related to different systems that have terminal E2 as the ground terminal are output simulta-
neously, terminal E2 may have an open circuit.

Read freeze frame data using the hand-held tester. Freeze frame data records the engine conditions
when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the
vehicle was running or stopped, if the engine was warmed up or not, if the air±fuel ratio was lean or
rich, as well as other data from the time when a malfunction occurred.

DI±116
± DIAGNOSTICSENGINE
310 Author: Date:
2005 SEQUOIA (RM1146U)
1 Connect hand±held tester, and read value of intake air temperature.
PREPARATION:
(a) Connect the hand±held tester to the DLC3.
(b) Turn the ignition switch ON and push the hand±held tester main switch ON.
(c) When using hand±held tester, enter the following menu: DIAGNOSIS / ENHANCED OBD II / DATA
LIST / ALL / INTAKE AIR.
CHECK:
Read the temperature value on the hand±held tester.
OK:
Same as actual intake air temperature.
RESULT:
Displayed TemperatureProceed to
±40°C (±40°F)A
140°C (284°F) or moreB
OK (Same as present temperature)C
HINT:

If there is an open circuit, the hand±held tester indicates ±40°C (±40°F).

If there is a short circuit, the hand±held tester indicates 140°C (284°F) or more.
B Go to step 4.
C Check for intermittent problems
(See page DI±11).
A