coolant TOYOTA SEQUOIA 2001 Service Service Manual

± DIAGNOSTICSENGINE
DI±151
345 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR STRATEGY
P0136
Heated rear oxygen sensor (Bank 1) output volt-
age (Output voltage)
P0136Heated rear oxygen sensor (Bank 1) impedance
(Low)
P0137
Heated rear oxygen sensor (Bank 1) output volt-
age (Low voltage)
P0137Heated rear oxygen sensor (Bank 1) impedance
(High)
P0138
Heated rear oxygen sensor (Bank 1) output volt-
age (High voltage)
RltdDTC
P0138Heated rear oxygen sensor (Bank 1) output volt-
age (Extremely high)
Related DTCs
P0156
Heated rear oxygen sensor (Bank 2) output volt-
age (Output voltage)
P0156Heated rear oxygen sensor (Bank 2) impedance
(Low)
P0157
Heated rear oxygen sensor (Bank 2) output volt-
age (Low voltage)
P0157Heated rear oxygen sensor (Bank 2) impedance
(High)
P0158
Heated rear oxygen sensor (Bank 2) output volt-
age (High voltage)
P0158Heated rear oxygen sensor (Bank 2) output volt-
age (Extremely high)
Rid / tMain sensors/componentsHeated rear oxygen sensorRequired sensors/componentsRelated sensors/componentsMass air flow meter
Frequency of operationOnce per driving cycle: Active air±fuel ratio control detection
Continuous: Others
Duration
20 sec.: Heated oxygen sensor output (Output voltage, High voltage, Low voltage)
30 sec.: Heated oxygen sensor impedance (Low)
90 sec.: Heated oxygen sensor impedance (High)
10 sec.: Heated oxygen sensor impedance (Extremely high)
MIL operation2 driving cycles Heated oxygen sensor output (Output voltage, High voltage, Low voltage)
Immediate: Heated oxygen sensor impedance (Low, High, Extremely high)
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever these
DTCs are not presentSee page DI±18
Heated oxygen sensor output voltage (Output voltage, High voltage and Low voltage):
Active air±fuel ratio controlExecuting
Active air±fuel ratio control being when all
of following conditions met±
Battery voltage11 V±
Engine coolant temperature75°C (167°F)±
IdleOFF
Engine RPM±3,200 rpm

DI±166
± DIAGNOSTICSENGINE
360 Author: Date:
2005 SEQUOIA (RM1146U)DTC No.
DTC Detecting ConditionTrouble Area
P0171
P0174When air±fuel ratio feedback is stable after warming up the
engine, fuel trim is considered to be in error on LEAN side
(2 trip detection logic)

Air induction system

Injector blockage

Mass air flow meter

Engine coolant temperature sensor

Fuel pressure

Gas leakage in exhaust system

Open or short in heated oxygen sensor (bank 1, 2 sensor 1)
circuit

Heated oxygen sensor (bank 1, 2 sensor 1)

Heated oxygen sensor heater (bank 1, 2 sensor 1)

EFI relay

PCV piping

ECM
P0172
P0175When air±fuel ratio feedback is stable after warming up the
engine, fuel trim is considered to be in error on RICH side
(2 trip detection logic)

Injector leak, blockage

Mass air flow meter

Engine coolant temperature sensor

Ignition system

Fuel pressure

Gas leakage in exhaust system

Open or short in heated oxygen sensor (bank 1, 2 sensor 1)
circuit

Heated oxygen sensor (bank 1, 2 sensor 1)

ECM
HINT:

When DTC P0171 or P0174 is recorded, the actual air±fuel ratio is on the LEAN side. When DTC
P0172 or P0175 is recorded, the actual air±fuel ratio is on the RICH side.

If the vehicle runs out of fuel, the air±fuel ratio is LEAN and DTC P0171 or P0174 may be recorded.
The MIL then comes on.

If the total of the short±term fuel trim value and long±term fuel trim value is within
35 % (engine cool-
ant temperature is more than 75 C (167F)), the system is functioning normally.

B17394
Fuel
Compensation
Amount
1.35
1.0
0.65 +35 (%):
Lean Malfunction Threshold
±35 (%):
Rich Malfunction Threshold
P0171, P0174:
P0172, P0175:
± DIAGNOSTICSENGINE
DI±167
361 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR DESCRIPTION
Under closed±loop fuel control, fuel injection volumes that deviate from those estimated by the ECM cause
changes in the long±term fuel trim compensation value. The long±term fuel trim is adjusted when there are
persistent deviations in the short±term fuel trim values. Deviations from the ECM's estimated fuel injection
volumes also affect the average fuel trim learning value, which is a combination of the average short±term
fuel trim (fuel feedback compensation value) and the average long±term fuel trim (learning value of the air±
fuel ratio). If the average fuel trim learning value exceeds the malfunction thresholds, the ECM interprets
this a fault in the fuel system and sets a DTC.
Example:
The average fuel trim leaning value is more than +35 % or less than ±35 %, the ECM interprets this as a fuel
system malfunction.
MONITOR STRATEGY
P0171Fuel system lean (Bank 1)
RltdDTCP0172Fuel system rich (Bank 1)Related DTCsP0174Fuel system lean (Bank 2)
P0175Fuel system rich (Bank 2)
Main sensors/componentsFront oxygen sensor
Required sensors/componentsRelated sensors/componentsEngine coolant temperature sensor, Mass air flow
meter, Crankshaft position sensor
Frequency of operationContinuous
Duration10 sec.
MIL operation2 driving cycles
Sequence of operationNone

± 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

DI±172
± DIAGNOSTICSENGINE
366 Author: Date:
2005 SEQUOIA (RM1146U)Rich
RichActual air±fuel ratio rich'

Injector leakage or blockage

Gas leakage from exhaust system

Ignition system

Fuel pressure

MAF meter

ECT sensor
A
LeanLean/RichA/F sensor malfunction'
A/F sensorB
RichLean/RichA/F sensor malfunction'
A/F sensorB
Lean: During A/F CONTROL, the A/F sensor output voltage (AFS) is consistently more than 3.35 V, and the
HO2 sensor output voltage (O2S) is consistently less than 0.4 V.
Rich: During A/F CONTROL, the AFS is consistently less than 3.0 V, and the O2S is consistently more than
0.55 V.
B Go to step 11.
C Go to step 15.
A
5 Read value of engine coolant temperature.
PREPARATION:
(a) Connect the hand±held tester to the DLC3.
(b) Turn the ignition switch to ON and turn the tester ON.
(c) Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / COOLANT
TEMP.
CHECK:
(a) Read the COOLANT TEMP twice, when the engine is cold and also when warmed up.
Standard:
With cold engine: Same as ambient air temperature.
With warm engine: Between 75C and 95C (167F and 203F)
NG Replace engine coolant temperature sensor.
OK

± DIAGNOSTICSENGINE
DI±173
367 Author: Date:
2005 SEQUOIA (RM1146U)
6 Read value of mass air flow meter.
PREPARATION:
(a) Connect the hand±held tester to the DLC3.
(b) Turn the ignition switch to ON and turn the tester ON.
(c) Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / MAF and
COOLANT TEMP.
(d) Allow the engine to idle until the COOLANT TEMP reaches 75C (167F) or more.
CHECK:
(a) Read the MAF with the engine in an idling condition and at an engine speed of 2,500 rpm.
Standard:
MAF while engine idling: Between 1.4 gm/s and 2.3 gm/s (shift position: N, A/C: OFF).
MAF at engine speed of 2,500 rpm: Between 5.4 gm/s and 7.9 gm/s (shift position: N, A/C: OFF).
NG Replace mass air flow meter.
OK
7 Check fuel pressure (See page SF±7).
CHECK:
Check the fuel pressure (high or low pressure).
NG Check and replace fuel pump, pressure regula-
tor, fuel pipe line and filter (See page SF±1).
OK
8 Check exhaust system for gas leakage.
OK:
No exhaust gas leakage.
NG Repair or replace exhaust gas leakage point.
OK

A20646
20 V
/Division Injector Signal Waveform
20 V
/Division
GND
100 msec./Division (Idling)(Magnification)
GND
1 msec./Division (Idling)
Injection duration
± DIAGNOSTICSENGINE
DI±185
379 Author: Date:
2005 SEQUOIA (RM1146U)DTC No.
DTC Detecting ConditionTrouble Area
P0300Misfiring of random cylinders is detected

Open or short in engine wire

Connector connection

Vacuum hose connection
P0301
P0302
P0303
P0304
P0305
P0306
P0307
P0308
Misfiring of each cylinder is detected

Vacuum hose connection

Ignition system

Injector

Fuel pressure

Mass air flow meter

Engine coolant temperature sensor

Compression pressure

Valve clearance

Valve timing

PCV piping

ECM
HINT:
When several codes for a misfiring cylinder are recorded repeatedly but no random misfire code is recorded,
it indicates that the misfires have been detected and recorded at different times.
Reference: Inspection using the oscilloscope.
With the engine idling, check the waveform between terminals #1 to #8 and E01 of the ECM connectors.
HINT:
The correct waveform is as shown in the illustration.

Crankshaft position sensor
(36±2 teeth or 12 teeth) Camshaft position sensor
ECM
A20490
DI±186
± DIAGNOSTICSENGINE
380 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR DESCRIPTION
The ECM illuminates the MIL (2 trip detection logic) if:
The ECM will illuminate the MIL when the percentage of misfire exceeds the specified limit per 1,000 engine
revolutions. One occurrence of excessive misfire during engine start will set the MIL. Four occurrences are
required to set the MIL 1,000 revolutions after engine start.
The ECM blinks the MIL (the MIL blinks immediately) if:

Within 200 engine revolutions at a high rpm, the threshold for ºpercentage of misfire causing catalyst
damageº is reached 1 time.

Within 200 engine revolutions at a normal rpm, the threshold for ºpercentage of misfire causing catalyst
damageº is reached 3 time.
MONITOR STRATEGY
P0300Random/Multiple cylinder misfire detected
P0301Cylinder 1 misfire detected
P0302Cylinder 2 misfire detected
P0303Cylinder 3 misfire detected
Related DTCsP0304Cylinder 4 misfire detectedRelated DTCs
P0305Cylinder 5 misfire detected
P0306Cylinder 6 misfire detected
P0307Cylinder 7 misfire detected
P0308Cylinder 8 misfire detected
Rid / t
Main sensors/componentsCamshaft position sensor, Crankshaft position
sensor
Required sensors/components
Related sensors/componentsEngine coolant temperature sensor, Intake air
temperature sensor, Throttle position sensor
Frequency of operationContinuous
DurationEvery 1,000 revolutions (soon after engine is started: 1 time, other: 4 times) (emission related misfire)
Every 200 revolutions (1 or 3 times) (catalyst deteriorating misfire)
MIL operation2 driving cycles MIL ON
Immediate MIL blinking (Catalyst deteriorating misfire)
Sequence of operationNone

± DIAGNOSTICSENGINE
DI±187
381 Author: Date:
2005 SEQUOIA (RM1146U)
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever these
DTCs are not presentSee page DI±18
Battery voltage8 V±
Throttle position learningCompleted
VVT systemNormal operate by scan±tool
Engine RPM400 to 5,700rpm
All of the following conditions are met:Condition 1 and 2
1. Engine coolant temperature±10C (14F)±
2. Either of the following conditions is met:Condition (a) or (b)
(a) Engine coolant temperature at engine
start±7C (19F)±
(b) Engine coolant temperature20C (68F)±
Fuel±cutOFF
Emission±related±misfire:
First 1,000 revolutions after engine start,
or check modeCrankshaft 1,000 revolutions
Except aboveCrankshaft 1,000 revolutions x 4
Catalyst±damage±misfire (MIL blinks):
All of the following conditions 1, 2 and 3
are metCrankshaft 200 revolutions
1. Driving cycle1st
2. Check modeOFF
3. Engine RPM±2,800 rpm
Except aboveCrankshaft 200 revolutions x 3
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
Emission±related±misfire:
Misfire rate:1.2 % or more
Catalyst±damage±misfire (MIL blinks):
Number of misfire per 200 revolutions93 or more
(varies with intake air amount and RPM)
Multiple cylinders misfireDetected
MONITOR RESULT
Refer to page DI±26 for detailed information.
The test value and test limit information are described as shown in the following table. Check the monitor
result and test values after performing the monitor drive pattern (refer to ºConfirmation Monitorº).

MID (Monitor Identification Data) is assigned to each emissions±related component.

TID (Test Identification Data) is assigned to each test value.

Scaling is used to calculate the test value indicated on generic OBD ll scan tools.

± DIAGNOSTICSENGINE
DI±191
385 Author: Date:
2005 SEQUOIA (RM1146U)
HINT:
In order to memorize the DTC of misfire, it is necessary to drive around MISFIRE RPM, MISFIRE LOAD in
the DATA LIST for the following period of time. Take care not to turn the ignition switch OFF. Turning the
ignition switch OFF switches the diagnosis system from check mode to normal mode, and all DTCs, etc.,
are erased.
Engine SpeedTime
Idling3 minutes 30 seconds or more
1,000 rpm3 minutes or more
2,000 rpm1 minute 30 seconds or more
3,000 rpm1 minute or more
(f) Check if there is misfire, and the DTC and the freeze frame data. Record the DTC's, freeze frame data
and misfire counter data.
(g) Turn the ignition switch OFF and wait for at least 5 seconds.
INSPECTION PROCEDURE
HINT:

If DTCs besides misfire DTCs are memorized simultaneously, troubleshoot the non±misfire DTCs first.

If the misfire does not occur when the vehicle is brought to the workshop, the misfire can be confirmed
by reproducing the condition of the freeze frame data. Also, after finishing the repair, confirm that there
is no misfire (See confirmation driving pattern).

On 6 or 8 cylinder engines, misfiring cylinder identification is disabled at high engine speed and only
a general misfire fault code P0300 is stored instead of a cylinder specific misfire fault code (P0301 to
P0308).
If the misfire starts in a high engine speed area or the misfire occurs only in a high engine speed area,
only code P0300 may be stored.
When only a general misfire fault code like P0300 is stored:

Erase the general misfire fault code using the hand±held tester

Start the engine and drive the confirmation patten.

Read the value of the misfire ratio for each cylinder. Or read the DTC.

Repair the cylinder that has a high misfire ratio. Or repair the cylinder indicated by the DTC.

After finishing repairs, drive the confirmation pattern again and confirm that no misfire occurs.

When either of SHORT FT #1, LONG FT #1, SHORT FT #2 or LONG FT #2 in the freeze frame data
is over the range of ±20 %, there is a possibility that the air±fuel ratio is becoming RICH (±20 % or
less) or LEAN (+20 % or more).

When COOLANT TEMP in the freeze frame data is less than 80°C (176°F), there is a possibility of
misfire only during engine warm±up.

If the misfire cannot be reproduced, the following reasons may apply: 1) the vehicle has low fuel, 2)
improper fuel is being used, or 3) the ignition plug is contaminated.

Be sure to check the value on the misfire counter after the repair.