speed sensor TOYOTA SEQUOIA 2001 Service Owner's Guide

A20488A21045
Threshold
(75C (167F))Estimated ECT
5 sec.
Indicated coolant temp. reading
DTC set (after 2 driving cycle) ECT
Time DI±142
± DIAGNOSTICSENGINE
336 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P0128 Coolant Thermostat (Coolant Temperature
Below Thermostat Regulating Temperature)
HINT:
This is the purpose of ºthermostatº malfunction detection.
CIRCUIT DESCRIPTION
If the engine coolant temperature does not reach 75°C (167°F) despite sufficient warm±up time has
elapsed.
DTC No.DTC Detection conditionTrouble Area
P0128
Condition (a), (b) and (c) are met:
(a) Cold start
(b) After sufficient warm±up time has elapsed
(c) Engine coolant temperature greater than 75°C (167°F)
Thermostat

Cooling system

Engine coolant temperature sensor

ECM
MONITOR DESCRIPTION
The ECM estimates the coolant temperature based on starting temperature, engine loads, and engine
speeds. The ECM then compares the estimated temperature with the actual ECT (Engine Coolant Tempera-
ture). When the estimated coolant temperature reaches 75C (167F), the ECM checks the actual ECT. If
the actual ECT is less than 75C (167F), the ECM will interpret this as a fault in the thermostat or engine
cooling system and set a DTC.
DICEQ±02

± DIAGNOSTICSENGINE
DI±143
337 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR STRATEGY
Related DTCsP0128Thermostat
Rid / t
Main sensors/componentsEngine coolant temperature sensor, Engine
cooling system, Thermostat
Required sensors/components
Related sensors/componentsIntake air temperature sensor, Vehicle speed
sensor
Frequency of operationOnce per driving cycle
Duration15 min.
MIL operation2 driving cycles
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever this DTC is
not presentSee page DI±18
Battery voltage11.0 V±
Throttle position learningCompleted
Either of the following conditions is metCondition 1 or 2
1. All of the following conditions are metCondition (a), (b) and (c)
(a) ECT at engine start ± IAT at engine
start±15 to 7C (±27 to 12.6F)
(b) ECT at engine start±10 to 56C (14 to 133F)
(c) IAT at engine start±10 to 56C (14 to 133F)
2. All of the following conditions are metCondition (a), (b) and (c)
(a) ECT at engine start ± IAT at engine
start±7C (12.6F)±
(b) ECT at engine start±56C (133F)
(c) IAT at engine start±10C (14F)±
Accumulated time that vehicle speed is 80
mph (128 km/h) or more±20 sec.
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
Duration that both of following conditions 1 and 2 are met5 sec. or more
1. Estimated engine coolant temperature75C (167F) or more
2. Engine coolant temperature sensor outputLess than 75C (167F)
COMPONENT OPERATING RANGE
ParameterStandard Value
Engine coolant temperature sensor output value after warm
up75C (167F) or more

A23661
Vehicle Speed
(64 km/h and 113 km/h)Between
40 mph and 70 mph
Idling
Ignition Switch OFF
10 minutes
Time Warm up
(Note: Even if vehicle stops during driving pattern, test can be resumed)NOTICE:
This test will not be completed
if the vehicle is driven under
absolutely constant speed
conditions such as with cruise
control activated. (h)
(g)
MISFIRE MON ..................... AVAILREADINESS TESTS
CAT EVAL ......................... INCMPL
HTD CAT EVAL ...................... N/A
EVAP EVAL ....................... INCMPL
2nd AIR EVAL .......................... N/A
A/C EVAL ................................ N/A
O2S EVAL ........................ INCMPL
O2S HTR EVAL .................. INCMPL
EGR EVAL ...............................N/A COMP MON ........................ AVAIL FUEL SYS MON ................... AVAIL
A76855
A23660
DI±154
± DIAGNOSTICSENGINE
348 Author: Date:
2005 SEQUOIA (RM1146U)
CONFIRMATION DRIVING PATTER
HINT:

This confirmation driving pattern is used in steps 5, 8 and 11 of the following diagnostic troubleshooting
procedure when using either a hand±held tester.

Performing this confirmation pattern will activate the Heated Oxygen (HO2) sensor monitor. (The cata-
lyst monitor is performed simultaneously.) This is very useful for verifying the completion of a repair.
(a) Connect a hand±held tester to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the tester or scan tool ON.
(d) Clear DTCs (where set) (see page DI±43).
(e) If using a hand±held tester, select the following menu
items: DIAGNOSIS / CARB OBD II / READINESS
TESTS.
(f) Check that O2S EVAL is INCMPL (incomplete).
(g) Start the engine and warm it up.
(h) Drive the vehicle at between 40 mph and 70 mph (64 km/h
and 113 km/h) for at least 10 minutes.
(i) Note the state of the Readiness Tests items. Those items
will change to COMPL (complete) as O2S EVAL monitor
operates.
(j) On the tester, select the following menu items: DIAGNO-
SIS / ENHANCED OBD II / DTC INFO / PENDING
CODES and check if any DTCs (any pending DTCs) are
set.
HINT:
If O2S EVAL does not change to COMPL, and any pending
DTCs fail to set, extend the driving time.

± DIAGNOSTICSENGINE
DI±155
349 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
HINT:
Hand±held tester only:
Narrowing down the trouble area is possible by performing ACTIVE TEST of the following ºA/F CONTROLº
(Heated oxygen sensor or another can be distinguished).
(a) Perform ACTIVE TEST by hand±held tester (A/F CONTROL).
HINT:
ºA/F CONTROLº is the ACTIVE TEST which changes the injection volume to ±12.5 % or +25 %.
(1) Connect the hand±held tester to the DLC3 on the vehicle.
(2) Turn the ignition switch ON.
(3) Warm up the engine with the engine speed at 2,500 rpm for approximately 90 seconds.
(4) Select the menu ºDIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROLº.
(5) Perform ºA/F CONTROLº with the engine in an idle condition (press the right or left button).
RESULT:
Heated oxygen sensor reacts in accordance with increase and decrease of injection volume
+25 % " rich output: More than 0.5 V
±12.5 % " lean output: Less than 0.4 V
NOTICE:
There is a few seconds delay in the sensor 1 (front sensor) output. And there is approximately 20
seconds delay in the sensor 2 (rear sensor).

± DIAGNOSTICSENGINE
DI±159
353 Author: Date:
2005 SEQUOIA (RM1146U)
6 Check whether DTC output recurs (DTC P0138, P0158)
CHECK:
(a) On the hand±held tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC
INFO / CURRENT CODES.
(b) Read DTCs.
RESULT:
Display (DTC Output)Proceed To
P0138 or P0158A
No outputB
B Check for intermittent problems
(See page DI±11).
A
Replace heated oxygen sensor.
7 Check output voltage of heated oxygen sensor.
PREPARATION:
(a) Connect the hand±held tester to the DLC3.
(b) Turn the ignition switch to ON and turn the tester ON.
(c) Start the engine.
(d) Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / O2S B1S2.
(e) After warming up the engine, run the engine at an engine speed of 2,500 rpm for 3 minutes.
CHECK:
(a) Read the output voltage of the HO2 sensor when the engine rpm is suddenly increased.
HINT:
Quickly accelerate the engine to 4,000 rpm 3 times using the accelerator pedal.
Standard: Fluctuates between 0.4 V or less and 0.5 V or more.
NG Go to step 14.
OK
8 Perform confirmation driving pattern.
NEXT

DI±168
± DIAGNOSTICSENGINE
362 Author: Date:
2005 SEQUOIA (RM1146U)
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever these
DTCs are not presentSee page DI±18
Battery voltage11 V±
Fuel system statusClosed±loop
Throttle position learningCompleted
Either of the following conditions is met:Condition 1 or 2
1. Engine RPM±1,000 rpm
2. Intake air amount per revolution0.26 g/sec.±
Catalyst monitorNo executed
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
Purge±cutExecuting
Either of the following conditions is metCondition 1 or 2
1. Average between short±term fuel trim and long±term fuel
trim35% or more (varies with ECT)
2. Average between short±term fuel trim and long±term fuel
trim±35% or less (varies with ECT)
WIRING DIAGRAM
Refer to DTC P2195 on page DI±383.
INSPECTION PROCEDURE
HINT:
Hand±held tester only:
Malfunctioning areas can be identified by performing the A/F CONTROL function provided in the ACTIVE
TEST. The A/F CONTROL function can help to determine whether the Air±Fuel Ratio (A/F) sensor, Heated
Oxygen (HO2) sensor and other potential trouble areas are malfunctioning.
The following instructions describe how to conduct the A/F CONTROL operation using a hand±held tester.
(1) Connect a hand±held tester to the DLC3.
(2) Start the engine and turn the tester ON.
(3) Warm up the engine at an engine speed of 2,500 rpm for approximately 90 seconds.
(4) On the tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / ACTIVE
TEST / A/F CONTROL.
(5) Perform the A/F CONTROL operation with the engine in an idling condition (press the RIGHT
or LEFT button to change the fuel injection volume).
(6) Monitor the voltage outputs of the A/F and HO2 sensors (AFS B1S1 (AFS B2S1) and OS2 B1S2
(O2S B2S2)) displayed on the tester.
HINT:

The A/F CONTROL operation lowers the fuel injection volume by 12.5 % or increases the injection
volume by 25 %.

Each sensor reacts in accordance with increases and decreases in the fuel injection volume.

± DIAGNOSTICSENGINE
DI±171
365 Author: Date:
2005 SEQUOIA (RM1146U)
3 Check air induction system (See page SF±1).
CHECK:
Check the air induction system for vacuum leaks.
NG Repair or replace air induction system.
OK
4 Perform active test (A/F control).
(a) Connect the hand±held tester to the DLC3.
(b) Start the engine and turn the tester ON.
(c) Warm up the engine at an engine speed of 2,500 rpm for approximately 90 seconds.
(d) On the tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST /
A/F CONTROL.
(e) Perform the A/F CONTROL operation with the engine in an idling condition (press the RIGHT or LEFT
button to change the fuel injection volume).
(f) Monitor the voltage outputs of A/F and HO2 sensors(AFS B1S1 (AFS B2S1) and O2S B1S2 (O2S
B2S2)) displayed on the tester.
HINT:

The A/F CONTROL operation lowers the fuel injection volume by 12.5 % or increases the injection
volume by 25 %.

Each sensor reacts in accordance with increases and decreases in the fuel injection volume.
Standard:
Tester Display
(Sensor)Injection VolumesStatusVoltages
AFS B1S1 (AFS B2S1)
(A/F)+25 %RichLess than 3.0
AFS B1S1 (AFS B2S1)
(A/F)±12.5 %LeanMore than 3.35
O2S B1S2 (O2S B2S2)
(HO2)+25 %RichMore than 0.55
O2S B1S2 (O2S B2S2)
(HO2)±12.5 %LeanLess than 0.4
Result:
Status
AFS B1S1
(AFS B2S1)Status
O2S B1S2
(O2S B2S2)A/F Condition and
A/F Sensor ConditionMisfiresSuspected Trouble AreasProceed To
Lean/RichLean/RichNormal''C
LeanLeanActual air±fuel ratio leanMay occur

PCV valve and hose

PCV hose connections

Injector blockage

Gas leakage from exhaust system

Air induction system

Fuel pressure

Mass Air Flow (MAF) meter

Engine Coolant Temperature (ECT)
sensor
A

A21043
Starter Relay EFI Relay
Circuit Opening
Relay
Fuel Pump RelayMREL
FPRTr2
Tr1 EFI No.1
IGNECM
FC
NE Fuel Pump
Battery
StarterFuel Pump Resistor
AM2Ignition Switch
STA
Crankshaft Position
Sensor (NE Signal)
± DIAGNOSTICSENGINE
DI±179
373 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P0230 Fuel Pump Primary Circuit
CIRCUIT DESCRIPTION
In the diagram below, when the engine is cranked, current flows from terminal STAR of the ECM to the starter
relay coil and also current flows to terminal STA of the ECM (STA signal).
When the STA signal and NE signal are input to the ECM, the Tr1 is turned ON, current flows to the coil of
the circuit opening relay, the relay switches on, power is supplied to the fuel pump, and the fuel pump oper-
ates.
While the NE signal is generated (engine running), the ECM keeps the Tr1 ON (circuit opening relay ON)
and the fuel pump also keeps operating.
The fuel pump speed is controlled at two levels (high speed or low speed) by the condition of the engine
(starting, light load, heavy load). When the engine starts (STA ON), the Tr2 in the ECM is OFF, so the fuel
pump relay closes and battery positive voltage is applied directly to the fuel pump. The fuel pump operates
at high speed.
After the engine starts while idling or light loads, since the Tr2 goes ON, power is supplied to the fuel pump
via the fuel pump resistor. The fuel pump operates at low speed.
DICEW±02

DI±184
± DIAGNOSTICSENGINE
378 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P0300 Random/Multiple Cylinder Misfire Detected
DTC P0301 Cylinder 1 Misfire Detected
DTC P0302 Cylinder 2 Misfire Detected
DTC P0303 Cylinder 3 Misfire Detected
DTC P0304 Cylinder 4 Misfire Detected
DTC P0305 Cylinder 5 Misfire Detected
DTC P0306 Cylinder 6 Misfire Detected
DTC P0307 Cylinder 7 Misfire Detected
DTC P0308 Cylinder 8 Misfire Detected
CIRCUIT DESCRIPTION
When a misfire occurs in the engine, hydrocarbons (HC) enter the exhaust in high concentrations. If this HC
concentration is high enough, there could be an increase in exhaust emission levels. High concentrations
of HC can also cause the temperature of the catalyst to increase, possibly damaging the catalyst. To prevent
this increase in emissions and limit the possibility of thermal damage, the ECM monitors the misfire rate.
When the temperature of the catalyst reaches a point of thermal degradation, the ECM will blink the MIL.
For monitoring misfire, the ECM uses both the camshaft position sensor and the crankshaft position sensor.
The camshaft position sensor is used to identify misfiring cylinders and the crankshaft position sensor is used
to measure variations in the crankshaft rotation speed. The misfire counter increments when crankshaft rota-
tion speed variations exceed threshold values.
If the misfiring rate exceeds the threshold value, which could cause emissions deterioration, the ECM illumi-
nates the MIL.
DID85±01

A23648
GND 1V/ DIV KNK1 Signal Waveform
1 msec./ Division
± DIAGNOSTICSENGINE
DI±205
399 Author: Date:
2005 SEQUOIA (RM1146U)
Reference: Inspection using the oscilloscope.
The correct waveform is as shown.
ItemDetails
Terminal
KNK1 ± EKNK
or
KNK2 ± EKN2
Equipment Settings0.01 to 10 V/Division,
0.01 to 10 msec./Division
ConditionAfter warming up the engine,
keep the engine speed at 4,000 rpm.
MONITOR DESCRIPTION
The knock sensor located on the cylinder block detects spark knock.
When spark knock occurs, the sensor pick±up vibrates in a specific frequency range. When the ECM detects
the voltage in this frequency range, it retards the ignition timing to suppress the spark knock.
If there is a defect in the knock sensor or an open or short circuit, the voltage level will deviate outside the
normal operating range. The ECM interprets this deviation as a defect in the knock sensor and sets a DTC.
Example:
When the knock sensor voltage output is less than 0.5 V, or more than 4.5 V, and if either the condition contin-
ues for more than 3 sec.
MONITOR STRATEGY
P0325Knock sensor (Bank 1) range check (Chattering)
P0327Knock sensor (Bank 1) range check (Low volt-
age)
RltdDTC
P0328Knock sensor (Bank 1) range check (High volt-
age)
Related DTCsP0330Knock sensor (Bank 2) range check (Chattering)
P0327Knock sensor (Bank 2) range check (Low volt-
age)
P0328Knock sensor (Bank 2) range check (High volt-
age)
Main sensors/componentsKnock sensor
Required sensors/componentsRelated sensors/components
Crankshaft position sensor, Camshaft position
sensor, Engine coolant temperature sensor,
Mass air flow meter
Frequency of operationContinuous
Duration1 sec.
MIL operationImmediate
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever these
DTCs are not presentSee page DI±18
Battery voltage10.5 V±
Time after engine start5 sec.±