2001 TOYOTA SEQUOIA terminal TC

A19288
B17411
HA1A
E7HA2A
± DIAGNOSTICSENGINE
DI±91
285 Author: Date:
2005 SEQUOIA (RM1146U)
2 Check A/F relay.
PREPARATION:
Remove the A/F relay from the engine room R/B No.2.
CHECK:
Inspect the A/F relay.
OK:
Standard:
Terminal No.ConditionSpecified Condition
3 ± 5Always10 KW or higher
3 ± 5Apply B+ between
terminals 1 and 2Below 1 W
NG Replace A/F relay.
OK
3 Check voltage between terminals HA1A, HA2A of ECM connectors and body
ground.
PREPARATION:
Turn the ignition switch ON.
CHECK:
Measure the voltage between terminals of the ECM connectors
and body ground.
HINT:

Connect terminal HA1A to the bank 1 sensor 1.

Connect terminal HA2A to the bank 2 sensor 1.
OK:
Standard:
Tester ConnectionSpecified Condition
HA1A (E7±2) ± Body ground9 V to 14 V
HA2A (E7±1) ± Body ground9 V to 14 V
OK Replace ECM (See page SF±80).
NG

A21341
+B
OX E1HT
H2
H4
Components Side:
Bank 1 Sensor 2, Bank 2 Sensor 2
A19288
EFI Relay
± DIAGNOSTICSENGINE
DI±99
293 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
HINT:
Read freeze frame data using hand±held tester. Because freeze frame records the engine conditions when
the malfunction is detected. When troubleshooting, it is useful to determine whether the vehicle was running
or stopped, the engine was warmed up or not, the air±fuel ratio was lean or rich, etc. when a malfunction
occurred.
1 Check resistance of heated oxygen sensor heater.
PREPARATION:
Disconnect the H2 or H4 heated oxygen sensor connector.
CHECK:
Measure resistance between terminals of the heated oxygen
sensor.
OK:
Standard:
Tester ConnectionSpecified Condition
HTL2 (H2±1) ± +B (H2±2)11 to 16 W (20°C)
HTR2 (H4±1) ± +B (H4±2)11 to 16 W (20°C)
NG Replace heated oxygen sensor.
OK
2 Check EFI relay.
PREPARATION:
Remove the EFI relay from the engine room J/B.
CHECK:
Inspect the EFI relay.
OK:
Standard:
Terminal No.ConditionSpecified Condition
3 ± 5Always10 KW or higher
3 ± 5Apply B+ between
terminals 1 and 2Below 1 W
NG Replace EFI relay.
OK

B17411
HT1B
E7HT2B
E8
DI±100
± DIAGNOSTICSENGINE
294 Author: Date:
2005 SEQUOIA (RM1146U)
3 Check voltage between terminals HT1B, HT2B of ECM connectors and body
ground.
PREPARATION:
Turn the ignition switch ON.
CHECK:
Measure the voltage between terminals of the ECM connectors
and body ground.
HINT:

Connect terminal HT1B to the bank 1 sensor 2.

Connect terminal HT2B to the bank 2 sensor 2.
OK:
Standard:
Tester ConnectionSpecified Condition
HT1B (E8±1) ± Body ground9 to 14 V
HT2B (E7±5) ± Body ground9 to 14 V
OK Replace ECM (See page SF±80).
NG

A21226
Wire Harness Side:
+B
Mass Air Flow Meter Connector
M1
B17411
VGE8E2G
ECM Connector
DI±106
± DIAGNOSTICSENGINE
300 Author: Date:
2005 SEQUOIA (RM1146U)
2 Check voltage of mass air flow meter power source.
PREPARATION:
(a) Disconnect the M1 mass air flow meter connector.
(b) Turn the ignition switch ON.
CHECK:
Measure voltage between terminal 1 of the mass air flow meter
connector and body ground.
OK:
Standard:
Tester ConnectionSpecified Condition
+B (M1±1) ± Body ground9 to 14 V
NG Go to step 5.
OK
3 Check voltage between terminal VG of ECM connector and body ground.
PREPARATION:
Start the engine.
CHECK:
Measure the voltage between the specified terminal of the E8
ECM connector.
HINT:
The shift position should be P or N and the A/C switch should
be turned OFF.
OK:
Standard:
Tester ConnectionConditionSpecified Condition
VG (E8±30) ±
E2G (E8±29)Engine is idling0.5 to 3.0 V
NG Replace ECM (See page SF±80).
NG

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.

± 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

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.