battery TOYOTA SEQUOIA 2001 Service Owner's Manual

DI±74
± DIAGNOSTICSENGINE
268 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR DESCRIPTION
After the ECM sends the ºtargetº duty±cycle signal to the OCV (Oil Control Valve), the ECM monitors the
OCV current to establish an ºactualº duty±cycle. When the actual duty±cycle ratio varies from the target
duty±cycle, the ECM sets a DTC.
MONITOR STRATEGY
RltdDTCP0010VVT oil control valve bank 1 range checkRelated DTCsP0020VVT oil control valve bank 2 range check
Required sensors/componentsOCV
Frequency of operationContinuous
Duration1 sec.
MIL operationImmediate
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever this DTC is
not presentSee page DI±18
Battery voltage11 V13 V
Target duty ratio±70%
StarterOFF
Current cut statusNot cut
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
Either of the following conditions is met:Condition 1 or 2
1. Output signal duty for OCVOutput duty ratio is 100% (always ON) but target duty ratio is less than 70%
2. Output signal duty for OCVOutput duty is 3% or less despite the ECM supplying current to the OCV
COMPONENT OPERATING RANGE
ParameterStandard Value
Output signal duty for OCVºMore than 3%º and ºless than 100%º

A31449A23511
Valve Battery ±
Battery +
DI±76
± DIAGNOSTICSENGINE
270 Author: Date:
2005 SEQUOIA (RM1146U)
1 Check OCV circuit.
PREPARATION:
(a) Connect the hand±held tester to the DLC3.
(b) Start the engine and warm it up.
(c) Turn the ignition switch to ON and turn the hand±held tester ON.
CHECK:
(a) Select the item: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / VVT CTRL B1 or VVT CTRL B2.
(b) Using the hand±held tester, operate the OCV and check the engine speed.
OK:
Standard:
Tester OperationSpecified Condition
OCV is OFFNormal engine speed
OCV is ONRough idle or engine stall
OK Check for intermittent problems
(See page DI±11).
NG
2 Check operation of OCV.
PREPARATION:
(a) Start the engine and warmed it up.
(b) Disconnect the OCV connector.
(c) Apply battery positive voltage between the terminals of
the OCV.
CHECK:
Check the engine speed.
OK:
Rough idle or engine stalled.
NG Replace OCV.
OK

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.

A23512
Reference (Bank 1 Sensor 1 System Drawing):
A/F Sensor A/F Relay
Heater
Sensor
A1A+ HA1A
Duty
Control ECM
From
Battery
A/F Heater
Fuse
A1A±
To EFI Relay DI±88
± DIAGNOSTICSENGINE
282 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P0031 Oxygen (A/F) Sensor Heater Control Circuit
Low (Bank 1 Sensor 1)
DTC P0032 Oxygen (A/F) Sensor Heater Control Circuit
High (Bank 1 Sensor 1)
DTC P0051 Oxygen (A/F) Sensor Heater Control Circuit
Low (Bank 2 Sensor 1)
DTC P0052 Oxygen (A/F) Sensor Heater Control Circuit
High (Bank 2 Sensor 1)
HINT:
Although each DTC title (DTC description) says ºoxygen sensorº, these DTCs are related to the ºA/F sensorº.
CIRCUIT DESCRIPTION
Refer to DTC P2195 on page DI±383.
HINT:
The ECM provides a pulse width modulated control circuit to adjust current through the heater. The A/F sen-
sor heater circuit uses a relay on the B+ side of the circuit.
DTC No.DTC Detection ConditionTrouble Area
P0031
P0051Heated current is 0.8 A or less when heater operates
(1 trip detection logic)
Open or short in heater circuit of A/F sensor

A/F sensor heater
P0032
P0052When the heater operates, heated current exceeds 19.7 A
(1 trip detection logic)
A/F sensor heater

A/F sensor heater relay

ECM
DIDFP±01

± 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.±

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.

± DIAGNOSTICSENGINE
DI±95
289 Author: Date:
2005 SEQUOIA (RM1146U)DTC No.
DTC Detecting ConditionTrouble Area
P0037Heater current is 0.25 A or less when the heater operates with

Open in heater circuit of heated oxygen sensor

Heated ox
ygen sensor heaterP0037
P0057
Heater current is 0.25 A or less when the heater o erates with
more than 10.5 V positive battery voltage

Heated oxygen sensor heater

EFI relay

ECM
P0038
P0058When heater operates, heater current exceeds 2.0 A

Short in heater circuit of heated oxygen sensor

Heated oxygen sensor heater

EFI relay

ECM
HINT:

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

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

Sensor 1 refers to the sensor closer to the engine assembly.

Sensor 2 refers to the sensor farther away from the engine assembly.
MONITOR DESCRIPTION
The sensing portion of the heated oxygen sensor has a zirconia element which is used to detect oxygen
concentration in the exhaust. If the zirconia element is at the proper temperature and difference of the oxy-
gen concentration between the inside and outside surface of sensor is large, the zirconia element will gener-
ate voltage signals. In order to increase the oxygen concentration detecting capacity in the zirconia element,
the ECM supplements the heat from the exhaust with heat from a heating element inside the sensor. When
current in the sensor is out of the standard operating range, the ECM interprets this as a fault in the heated
oxygen sensor and sets a DTC.
Example:
The ECM will set a high current DTC if the current in the sensor is more than 2.0 A when the heater is OFF.
Similarly, the ECM will set a low current DTC if the current is less than 0.3 A when the heater is ON.
MONITOR STRATEGY
P0037Rear HO2S heater (Bank 1) range check (Low
Current)
RltdDTC
P0038Rear HO2S heater (Bank 1) range check (High
Current)
Related DTCs
P0057Rear HO2S heater (Bank 2) range check (Low
Current)
P0058Rear HO2S heater (Bank 2) range check (High
Current)
Rid / tMain sensors/componentsHO2S heaterRequired sensors/componentsRelated sensors/componentsVehicle speed sensor (VSS)
Frequency of operationContinuous
Duration0.3 sec.
MIL operationImmediate
Sequence of operationNone

DI±96
± DIAGNOSTICSENGINE
290 Author: Date:
2005 SEQUOIA (RM1146U)
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever these
DTCs are not presentSee page DI±18
P0037, P0057 (Low current):
Battery voltage10.5 V±
All heater is turned OFF and intrusive
heating is operated when the following
conditions are met
Condition (a) and (b)
(a) HeaterON
(b) Heater current±0.3 A
P0038, P0058 (High current):
Case 1:
Battery voltage10.5 V±
EngineRunning
StarterOFF
Intrusive heatingNot operating
Case 2:
Battery voltage10.5 V±
All heater is turned OFF and intrusive
heating is operated when the following
conditions are met
Condition (a) and (b)
(a) HeaterON
(b) Heater current2 A±
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
P0037, P0057 (Low current):
HO2S heater current during intrusive heatingLess than 0.3 A (when battery voltage is 10.5 V or more)
P0038, P0058 (High current):
Case 1:
HO2S heater current2 A or more
Case 2:
HO2S heater current during intrusive heatingMore than 2 A
COMPONENT OPERATING RANGE
ParameterStandard Value
HO2S heater current0.4 to 1 A (at idle, warmed±up engine and +B: 11 to 14 V)

A23550
Battery 2FECM
OX1B HT2B
OX2B 33 Y
AG±R 3 2
ERB±W
EDW±B
5
4
5 1
22J2
IG4
HTR2
NTL2 OXR2
E8
F10
Fusible Link
Block G±R
EC 2D112H6
2A2 EFI Relay
EFI No. 1
EFI No. 2
J/C
IA4
G±R
HT1B 8
5
18
E8 E7
E7 E4
G±R G±R14
IA4 B±W
OXL21 4
A G±R Engine Room J/B
J42
J/CA
B J5
J/CW±R
E8
E6 G±W
BR
BR
H4 Heated Oxygen Sensor
(Bank 2 Sensor 2)
H2 Heated Oxygen Sensor
(Bank 1 Sensor 2)
J16
28
1 (Shielded) B
E B
EB J42
J/C G±W G±W
E1B
GJ/C
E1 +B
+B
E1 E2 MREL
(Shielded)
CC
C
BR DI±98
± DIAGNOSTICSENGINE
292 Author: Date:
2005 SEQUOIA (RM1146U)
WIRING DIAGRAM

F10
Fusible
Link
Block
A23554
ECM
VG
E2G 8
E4
30
E8
29
E8 B±W R±W
2
B IA414
BatteryB 2F1 2D1 Engine Room J/B
EFI No. 1 EFI Relay
EFI No. 2
5
3
1
2 2H2A2G±R J2
J/C
A
B G±R
IG422
G±R
3 IA44B±W
J16
J/C
6B
W±B G±RA
A
J5
J/C
ED
+B
VG
MREL
M1
Mass Air Flow Meter
B±W
G±R
1
4
5 E2G DI±104
± DIAGNOSTICSENGINE
298 Author: Date:
2005 SEQUOIA (RM1146U)
COMPONENT OPERATING RANGE
ParameterStandard Value
Mass air flow meter voltage0.4 to 2.2 V
WIRING DIAGRAM