2001 TOYOTA SEQUOIA fuel

A07621A09776
1
2L±W
P±LOC1+
OC1±
OC2+
OC2± 17
L±B
R±L 1
2E6 C13
OCV (Bank 1)
C14
OCV (Bank 2)ECM
16
15
14 E6
E6
E6
± DIAGNOSTICSENGINE
DI±75
269 Author: Date:
2005 SEQUOIA (RM1146U)
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:

If DTC P0010 displayed, check left bank OCV circuit.

If DTC P0020 displayed, check right bank OCV circuit.

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 for determining whether the ve-
hicle was running or stopped, the engine was warmed up or not, the air±fuel ratio was lean or rich, etc.
at the time of the malfunction.

DI±80
± DIAGNOSTICSENGINE
274 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR STRATEGY
P0011VVT system advance (Bank 1)
RltdDTCP0012VVT system retard (Bank 1)Related DTCsP0021VVT system advance (Bank 2)
P0022VVT system retard (Bank 2)
Main sensors/componentsCamshaft position sensor
Required sensors/componentsRelated sensors/componentsEngine coolant temperature sensor,
Crankshaft position sensor
Frequency of operationOnce per drive cycle
Duration10 sec.
MIL operationP0011, P0021: Immediate
P0012, P0022: 2 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±
Throttle position learningCompleted
Engine RPM400 rpm4,000 rpm
Engine coolant temperature75C (167F)100C (212F)
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
Deviation of valve timingMore than 5CA
OCV activation63 times or more
Response of valve timing1 sec./1CA or more
WIRING DIAGRAM
Refer to DTCs P0010 on page DI±73.
INSPECTION PROCEDURE
HINT:

Bank 1 refers to bank that includes cylinder No. 1.

Bank 2 refers to bank that does not include cylinder No. 1.

If DTC P0011, P0012 is displayed, check the bank 1 VVT system.

If DTC P0021, P0022 is displayed, check the bank 2 VVT system.

Read freeze frame data using the hand±held tester. Freeze frame data records the engine conditions
when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle
was running or stopped, the engine was warmed up or not, the air±fuel ratio was lean or rich, etc. at
the time of the malfunction.

A02961
V5
VVT Sensor (Bank 1)ECM
1
2R
G
Y
LVVL+
VVL±
VVR+
E5 18
19
19
18
VVR±
1
2E5
E4
E4 V6
VVT Sensor (Bank 2)
± DIAGNOSTICSENGINE
DI±87
281 Author: Date:
2005 SEQUOIA (RM1146U)
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:

If DTC P0016 is displayed, check left bank VVT sensor.

If DTC P0018 is displayed, check right bank VVT sensor.

Read freeze frame data using hand±held tester or OBD II scan tool. Because freeze frame records
the engine conditions when the malfunction is detected. When troubleshooting, it is useful for deter-
mining whether the vehicle was running or stopped, the engine was warmed up or not, the air±fuel ratio
was lean or rich, etc. at the time of the malfunction.
1 Check valve timing (Check for loose and jumping teeth of timing belt) (See page
EM±16).
NG Adjust valve timing (Repair or replace timing
belt).
OK
Replace ECM (See page SF±80).

± DIAGNOSTICSENGINE
DI±89
283 Author: Date:
2005 SEQUOIA (RM1146U)
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 closest to the engine assembly.

Sensor 2 refers to the sensor farthest away from the engine assembly.
MONITOR DESCRIPTION
The ECM uses the Air±Fuel Ratio sensor (A/F sensor) information to regulate the air±fuel ratio close to the
stoichiometric ratio. This maximizes the catalytic converter's ability to purify exhaust gases. The sensor de-
tects oxygen levels in the exhaust gas and sends this signal to the ECM.
The inner surface of the sensor element is exposed to outside air. The outer surface of the sensor element
is exposed to exhaust gas. The sensor element is made of platinum coated zirconia and includes an inte-
grated heating element. The zirconia element generates a small voltage when there is a large difference in
the oxygen concentrations of the exhaust and the outside air. The platinum coating amplifies the voltage
generation. When heated, the sensor becomes very efficient. If the temperature of the exhaust is low, the
sensor will not generate useful voltage signals without supplemental heating. The ECM regulates the sup-
plemental heating using a duty±cycle approach to regulate the average current in the heater element. If the
heater current is out of the normal range, the sensor's output signals will be inaccurate and the ECM can
not regulate the air±fuel ratio properly.
When the heater current is out of the normal operating range, the ECM interprets this as a malfunction and
sets a DTC.
MONITOR STRATEGY
P0031A/F sensor heater (Bank 1) range check (Low
current)
RltdDTC
P0032A/F sensor heater (Bank 1) range check (High
current)
Related DTCs
P0051A/F sensor heater (Bank 2) range check (Low
current)
P0052A/F sensor heater (Bank 2) range check (High
current)
Rid / tMain sensors/componentsA/F sensor heaterRequired sensors/componentsRelated sensors/components±
Frequency of operationContinuous
Duration10 sec.
MIL operationImmediate
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever these
DTCs are not presentSee page DI±18
P0031, P0051 (Low current):
Battery voltage10.5 V±
A/F sensor heater duty ratio50%±
Time after engine start10 sec.±

B17396
HT +B
AF± AF+ Sensor 1A/F Sensor Component Side:
Front View
DI±90
± DIAGNOSTICSENGINE
284 Author: Date:
2005 SEQUOIA (RM1146U) P0032, P0052 (High current):
Time after engine start10 sec.±
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
P0031, P0051 (Low current):
A/F sensor heater currentLess than 0.8 A
P0032, P0052 (High current):
A/F sensor heater currentMore than 10 A
COMPONENT OPERATING RANGE
ParameterStandard Value
A/F sensor heater current1.8 to 3.4 A at 20°C (68°F)
WIRING DIAGRAM
Refer to DTC P2195 on page DI±383.
INSPECTION PROCEDURE
HINT:
Read freeze frame data using a hand±held tester or OBD II scan tool. 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 resistance of air±fuel ratio (A/F) sensor heater.
PREPARATION:
Disconnect the air±fuel ratio (A/F) sensor connector.
CHECK:
Measure resistance between the terminals of the A/F sensor
connector.
OK:
Standard:
Tester ConnectionSpecified Condition
HT (1) ± +B (2)1.8 W to 3.4 W at 20C (68F)
HT (1) ± AF± (4)10 kW or higher
NG Replace air±fuel ratio (A/F) sensor.
OK

B17386
Housing
Solid Electrolyte
(Zirconia Element)
Platinum Electrode
Heater
Coating (Ceramic)
Exhaust Gas CoverIdeal Air±Fuel Mixture
Output Voltage
Richer ± Air Fuel Ratio ± Leaner
Atmospheric Air
A21040
Reference(Bank 1 Sensor 1 System Drawing) :
ECM
EFI Relay
EFI Fuse No. 1 From
Battery
GroundOX1A
MREL HT1A
Duty
Control Heater
Sensor Heated Oxygen Sensor
EFI Fuse No. 2
E2 DI±94
± DIAGNOSTICSENGINE
288 Author: Date:
2005 SEQUOIA (RM1146U)
CIRCUIT DESCRIPTION
To obtain a high purification rate for the CO, HC and NOx components of the exhaust gas, a three±way cata-
lytic converter is used, but for the most efficient use of the three±way catalytic converter, the air±fuel ratio
must be precisely controlled so that it is always close to the stoichiometric air±fuel ratio.
The heated oxygen sensor has the characteristic which its output voltage changes suddenly in the vicinity
of the stoichiometric air±fuel ratio. This characteristic is used to detect the oxygen concentration in the ex-
haust gas and provide the ECM with feedback to control the air±fuel ratio.
When the air±fuel ratio becomes LEAN, the oxygen concentration in the exhaust increases and the heated
oxygen sensor informs the ECM of the LEAN condition (low voltage, i.e. less than 0.45 V).
When the air±fuel ratio is RICHER than the stoichiometric air±fuel ratio, the oxygen concentration in the ex-
haust gas is reduced and the heated oxygen sensor informs the ECM of the RICH condition (high voltage,
i.e. more than 0.45 V). The ECM judges by the voltage output from the heated oxygen sensor whether the
air±fuel ratio is RICH or LEAN and controls the injection time accordingly. However, if malfunction of the
heated oxygen sensor causes output of abnormal voltage, this disables the ECM for performing an accurate
air±fuel ratio control. The heated oxygen sensors include a heater which heats the zirconia element. The
heater is controlled by the ECM. When the intake air volume is low (the temperature of the exhaust gas is
low) current flows to the heater to heat the sensor for accurate oxygen concentration detection.
HINT:
The ECM provides a pulse width modulated control circuit to adjust current through the heater. The heated
oxygen sensor heater circuit uses a relay on the B+ side of the circuit.

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

FI6929A09074A09707
Power Transistor
Output
Voltage
AB B+
Temperature Sensor
Platinum Hot Wire
Temperature Sensor
Platinum Hot Wire DI±102
± DIAGNOSTICSENGINE
296 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P0100 Mass or Volume Air Flow Circuit
DTC P0102 Mass or Volume Air Flow Circuit Low Input
DTC P0103 Mass or Volume Air Flow Circuit High Input
CIRCUIT DESCRIPTION
The Mass Air Flow (MAF) meter measures 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 incom-
ing air cools the wire and an internal thermistor, affecting their resistance. To maintain a constant current
value, the ECM varies the voltage applied to these components in the MAF meter. The voltage level is pro-
portional to the airflow through the sensor. The ECM interprets this voltage as the intake air amount.
The circuit is constructed so that the platinum hot wire and temperature sensor provide a bridge circuit, with
the power transistor controlled so that the potential of A and B remains equal to maintain the set temperature.
DTC No.DTC Detection ConditionTrouble Area
P0100Open or short in mass air flow meter circuit for more than 3
sec.
P0102Open or short in mass air flow meter circuit for more than 3
sec.
Open or short in mass air flow meter circuit

Mass air flow meter
P0103
Open in mass air flow meter circuit for more than 3 sec. (EVG
circuit)
Short in mass air flow meter circuit for more than 3 sec. (+B
circuit)
Mass air flow meter

ECM
DICEN±02