TOYOTA HIGHLANDER 2001 Service Repair Manual

- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
05-1 17
307 Author
: Date
:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
INSPECTION PROCEDURE
HINT:
Read freeze frame data using the hand-held tester or the OBD II scan tool. Freeze frame data records the
engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help deter-
mine if the vehicle was running or stopped, 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 COOLING SYSTEM
(a) Check the cooling system for excessive cooling, such as abnormal radiator fan operation, modified
cooling system and other defects.
NG REPAIR OR REPLACE COOLING SYSTEM
OK
2 INSPECT THERMOSTAT (See page 16-2)
(a) Check the valve opening temperature of the thermostat.
OK:
Valve opening temperature: 80 to 84C (176 to 183F)
HINT:
Also check that the valve is completely closed under opening temperature as above.
NG REPLACE THERMOSTAT(See page 16-1 1)
OK
REPLACE ECM(See page 10-9)

A90870
Atmosphere
Housing
Platinum Electrode
Solid Electrolyte
(Zirconia Element)
Platinum Electrode
Heater
Coating (Ceramic)
Exhaust Gas CoverIdeal Air-fuel Mixture
Output Voltage
Richer - Air Fuel Ratio - Leaner
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- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
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: Date
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2005 HIGHLANDER REPAIR MANUAL (RM1144U)
DTC P0136 OXYGEN SENSOR CIRCUIT MALFUNCTION
(BANK 1 SENSOR 2)
DTC P0137 OXYGEN SENSOR CIRCUIT LOW VOLTAGE
(BANK 1 SENSOR 2)
DTC P0138 OXYGEN SENSOR CIRCUIT HIGH VOLTAGE
(BANK 1 SENSOR 2)
CIRCUIT DESCRIPTION
The heated oxygen sensor (HO2S) is used to monitor oxygen in the exhaust gas. For optimum catalyst op-
eration, the air fuel mixture (air-fuel ratio) must be maintained near the ideal stoichiometric ratio. The HO2S
output voltage changes suddenly in the vicinity of the stoichiometric ratio. The ECM adjusts the fuel injection
time so that the air-fuel ratio is nearly stoichiometric.
The HO2S generates a voltage between 0.1 and 0.9 V in response to oxygen in the exhaust gas. If the oxy-
gen in the exhaust gas increases, the air-fuel ratio becomes Lean. The ECM interprets Lean when the HO2S
voltage is below 0.45 V. If the oxygen in the exhaust gas decreases, the air-fuel ratio becomes Rich. The
ECM interprets Rich when the HO2S voltage is above 0.45 V.
05ITJ-02

- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
05-1 19
309 Author
: Date
:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)DTC No.
DTC Detection ConditionTrouble Area

Following condition (a) (b) or (c) is met:
(a) During driving with engine warmed up, heated oxygen sen-
sor output does not change for 8 minutes
(b) Heated oxygen sensor output is very low most of time for

Open or short in heated oxygen sensor (bank 1 sensor 2)
ii
P0136
(b) Heated oxygen sensor out ut is very low most of time for
220 seconds
(c) The rear heated oxygen sensor voltage does not drop to
below 0.2 V immediately when vehicle decelerates and fuel
cut is operatingcircuit

Heated oxygen sensor (bank 1 sensor 2)

Heated oxygen sensor heater (bank 1 sensor 2)

A/F sensor


A/F sensor heatercut is o erating

Both (a) and (b) continue for more than 30 seconds:
(a) Estimated rear oxygen sensor temperature is less than
800C
(b) Rear oxygen sensor impedance is less than 5W
A/F sensor heater

EFI relay
P0137
Both (a) and (b) continue for more than 240 seconds:
(a) Estimated rear oxygen sensor temperature is more than
450C
(b) Rear oxygen sensor impedance is more than 15kW
Open or short in heated oxygen sensor (bank 1 sensor 2)
circuit (sensor to ECM)

Open or short in heated oxygen sensor (bank 1 sensor 2)
internal
P0138Rear oxygen sensor output voltage is over 1.2 V for more than
30 seconds
Short in heated oxygen sensor (bank 1 sensor 2) circuit

Short in heated oxygen sensor (bank 1 sensor 2) circuit

ECM internal circuit malfunction
MONITOR DESCRIPTION
The ECM monitors the rear heated oxygen sensor (HO2S) in the following 4 items:
1. The HO2S voltage changes between Rich (more than 0.45 V) and Lean (less than 0.45 V) while the vehicle
is running (repeating acceleration and deceleration) for 8 minutes. If not, the ECM interprets this as a mal-
function, illuminates the MIL, and then sets a DTC.
2. The HO2S voltage does not remain at less than 0.05 V for a long time while the vehicle is running (60 %
of the time in the 220 second-monitor, the sensor output is less than 0.05 V). If it does, the ECM interprets
this as a malfunction, illuminates the MIL, and then sets a DTC.
3. The sensor's voltage drops to below 0.2 V (extremely Lean status) immediately when the vehicle deceler-
ates and the fuel cut is working for 7 seconds. If not, the ECM interprets this to mean the sensor's response
feature has deteriorated, illuminates the MIL, and then sets a DTC.
4. The rear oxygen sensor impedance is 5 W or less, 15 kW or more, or output voltage is 1.2 V or more (normal
voltage: 0 to 1.0 V). If so, the ECM will determine that the rear oxygen sensor or a related circuit has an open
or short circuit, illuminates the MIL and sets a DTC.
Impedance is detected by the IC inside the ECM.
MONITOR STRATEGY
Related DTCs
P0136: Heated oxygen sensor output voltage (Output voltage)
P0136: Heated oxygen sensor impedance (Low impedance)
P0137: Heated oxygen sensor impedance (High impedance)
P0138: Heated oxygen sensor output voltage (High voltage)
P0138: Heated oxygen sensor output voltage (During fuel-cut)
Required Sensors/Components (Main)Heated oxygen sensor
Required Sensors/Components (Related)Crankshaft position sensor, engine coolant temperature sensor, mass air flow me-
ter and throttle position sensor
Frequency of OperationOnce per driving cycle: Active air-fuel ratio control detection
Continuous: Others
DurationWithin 480 seconds
MIL Operation
2 driving cycles: P0136 (Rear HO2S output voltage - case 1)
P0136 (Rear HO2S output voltage - case 2)
P0138 (Rear HO2S voltage during fuel-cut)
Immediate: Others
Sequence of OperationNone

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2005 HIGHLANDER REPAIR MANUAL (RM1144U)
TYPICAL ENABLING CONDITIONS
All:
The monitor will run whenever these DTCs are not presentSee page 05-16
P0136 (Rear HO2S output voltage - case 1):
All of the following conditions are met:Conditions 1, 2, 3 and 4
1. Malfunction determination in this driving cycleNot detected
2. EngineRunning
3. Time after engine start0 second or more
4. Either of the following conditions is met:Conditions (a) or (b)
(a) Cumulative time while HO2S heater is operating22 seconds or more
(b) HO2S voltageHas reached to 0.2 V or more
P0136 (Rear HO2S output voltage - case 2):
EngineRunning
P0136 (Rear HO2S low impedance):
Battery voltage11 V or more
Estimated HO2S temperatureLess than 700C (1,292F)
ECM monitorCompleted
P0606Not set
P0137 (Rear HO2S high impedance):
Battery voltage11 V or more
Estimated HO2S temperature450C (842F) or higher
ECM monitorCompleted
P0606Not set
P0138 (Rear HO2S output voltage - case 3):
Battery voltage11 V or more
Time after engine start2 seconds or more
P0138 (Rear HO2S output voltage during fuel-cut):
Engine coolant temperature70C (158F) or more
Catalyst temperature400C (752F) or more
Fuel-cutExecuting
TYPICAL MALFUNCTION THRESHOLDS
P0136 (Rear HO2S output voltage - case 1):
Both of the following conditions are met:Conditions 1 and 2
1. Frequency that HO2S voltage changes between (a) and
(b)0 time
(a) Maximum voltage0.6 V or more
(b) Minimum voltageLess than 0.45 V
2. Cumulative monitor time *1
of rear HO2S320 seconds or more
*1: Monitor time is counted when all of the following condi-
tions are met:Conditions (a) and (b)
(a) Fuel system statusClosed-loop
(b) IdleOFF
P0136 (Rear HO2S output voltage - case 2):
All of the following conditions are met:Conditions 1, 2, 3, 4 and 5
1. Cumulative monitor time *2
of HO2S220 seconds or more
2. Duration while HO2S voltage is below 0.05 V132 seconds or more
3. Duration while HO2S voltage is higher than 0.7 VLess than 44 seconds
4. Duration while HO2S voltage is 0.45 V to 0.7 VLess than 88 seconds
5. Duration while HO2S voltage is 0.45 V or moreLess than 20 seconds

- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
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2005 HIGHLANDER REPAIR MANUAL (RM1144U) *2: Monitor time is counted when all of the following condi-
tions are met:
Conditions 1, 2, 3 and 4
1. Intake air amount per revolution0.32 g/rev or more
2. Vehicle speed3 km/h (1.875 mph) or more
3. IdleOFF
4. Fuel-cutOFF
P0136 (Rear HO2S low impedance):
Duration of the following condition:30 seconds or more
Rear HO2S impedanceLess than 5 W
P0137 (Rear HO2S high impedance):
Duration of the following condition:90 seconds or more
Rear HO2S impedance15 kW or more
P0138 (Rear HO2S output voltage - case 3):
Duration of the following condition:10 seconds or more
Rear HO2S voltage1.2 V or more
P0138 (Rear HO2S output voltage during fuel-cut):
Either of the following conditions is met:Conditions 1 or 2
1. Duration until rear HO2S voltage drops to 0.2 V after fuel-
cut start7 seconds or more
2. Both of the following conditions are met:Conditions (a) and (b)
(a) Rear HO2S voltage when fuel-cut starts0.5 V or more
(b) Duration that HO2S voltage is 0.2 to 0.35 V1 second or more
COMPONENT OPERATING RANGE
HO2S voltageVaries between 0.1 and 0.9 V

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2005 HIGHLANDER REPAIR MANUAL (RM1144U)
O2S TEST RESULT
Refer to page 05-22 for detailed information.
HO2S Output voltage (Minimum and Maximum):
TEST IDDescription of TEST
VALUEConversion Factor (Unit)UnitStandard Value
$07Minimum HO2S voltageN/AVLess than TEST LIMIT
$08Maximum HO2S voltageN/AVMore than TEST LIMIT
$31Minimum time per one-
cycle of HO2S frequency
that HO2S switches Lean
to RichN/ASecondLess than TEST LIMIT
$32Minimum time per one-
cycle of HO2S frequency
that HO2S switches Rich
to LeanN/ASecondLess than TEST LIMIT
$37Time until HO2S voltage
drops to 0.2 V during fuel-
cutN/ASecondLess than TEST LIMIT
$81Percentage in monitoring
time while HO2S voltage is
lower than 0.05 VMultiply 0.39 %Less than TEST LIMIT
$84Percentage in monitoring
time while HO2S voltage is
higher than 0.7 VMultiply 0.39 %More than TEST LIMIT
$85Continuous time while
HO2S voltage is higher
than 0.45 VMultiply 0.262SecondMore than TEST LIMIT
$87Percentage in monitoring
time while HO2S voltage is
higher than 0.45 VMultiply 0.39 %More than TEST LIMIT

A90296
MRELOX1B
31HT1BECM
FL
Main
BatteryEngine
Room R/B
No. 2
J2
J/C W-B B-W
4H10
Heated Oxygen Sensor
BR
BR A
A 1
12D
EFI
Relay35
2 2
5
31Engine
Room
J/BB
EEE5 E8
E8
8 21
29
2
O1B- Shielded
E91
E1 ABR J7
J/CE8
ABR
EH F7
FL
Block
AssyW
W22
EFI
NO. 2
2B
2F 2I EFI
NO. 12
IM13
IM16
IM1R-Y
G
R
B P-LW B-R
GR
Y2 1
34
13
IK3
IM1 4 IM1
EB15
1
R HT
OX
E +B
- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
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2005 HIGHLANDER REPAIR MANUAL (RM1144U)
WIRING DIAGRAM

A58686
Vehicle speed
60 km/h
(38 mph)
Ignition Switch OFFOnce
40 seconds
or more
Warm up
(engine coolant
temperature
is more than 75C (167F)) 10 seconds
or moreTwice
40 seconds
or more12 times
40 seconds
or more
(a), (b)(d)
(e)
Idling (c)(d)
(e)(d)
(f)
10 seconds
or more10 seconds
or more 05-124
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2005 HIGHLANDER REPAIR MANUAL (RM1144U)
CONFIRMATION DRIVING PATTERN (P0136)
(a) Connect the hand-held tester to the DLC3.
(b) Switch the hand-held tester from normal mode to check (test) mode (see page 05-40).
(c) Start the engine and warm it up until the engine coolant temperature becomes more than 75C.
(d) Drive the vehicle at 60 km/h (38 mph) or more for 40 seconds or more.
(e) Let the engine idle for 10 seconds or more.
(f) Perform steps (d) to (e) 12 times.
HINT:
If a malfunction exists, the MIL will illuminate during step (f).
NOTICE:
If the conditions in this test are not strictly followed, detection of a malfunction will not occur. If you
do not have a hand-held tester, turn the ignition switch OFF after performing steps from (c) to (f), then
perform steps from (c) to (f) again.
CONFIRMATION DRIVING PATTERN (P0137)
Warm up the engine and run the engine at 60 km/h (38 mph) for 7 minutes.
CONFIRMATION DRIVING PATTERN (P0138)
Warm up the engine and run the engine at idle for 30 seconds.
INSPECTION PROCEDURE
HINT:
Hand-held tester only:
It is possible the malfunctioning area can be found using the ACTIVE TEST A/F CONTROL operation. The
A/F CONTROL operation can determine if the A/F sensor, heated oxygen sensor or other potential trouble
areas are malfunctioning or not.
(a) Perform the ACTIVE TEST A/F CONTROL operation.
HINT:
The A/F CONTROL operation lowers the injection volume 12.5 % or increases the injection volume 25 %.
(1) Connect the hand-held tester to the DLC3 on the vehicle.
(2) Turn the ignition switch ON.
(3) Warm up the engine by running the engine at 2,500 rpm for approximately 90 seconds.
(4) Enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL.
(5) Perform the A/F CONTROL operation with the engine idle (press the right or left button).

+25 %
-12.5 %
More than 3.35 V
Less than 3.0 V
Case 1
Case 2
Case 3
Case 4
Output voltage of A/F sensor
(sensor 1)
Injection volume
Output voltage
Output voltage of heated oxygen
sensor (sensor 2)Main suspect
trouble area
OK
+25 %
-12.5 %
More than 3.35 V
Less than 3.0V
Injection volume
Output voltage
+25 %
-12.5 %
More than 0.55 V
Less than 0.4V
Injection volume
Output voltage
A/F sensor
(A/F sensor, heater, A/F sen-
sor circuit)
+25 %
-12.5 %
More than 0.55 V
Less than 0.4V
Injection volume
Output voltage
+25 %
-12.5 %
Injection volume
Output voltage
NG
+25 %
-12.5 %
Injection volume
Output voltage
NG
+25 %
-12.5 %
Injection volume
Output voltage
NG
+25 %
-12.5 %
Injection volume
Output voltage
NGExtremely rich or lean actual
air-fuel ratio
(Injector, fuel pressure, gas
leakage in exhaust system,
etc.) OK
OK
OK
Almost
No reaction
Almost
No reaction
Almost
No reaction Almost
No reaction
'
Heated oxygen sensor
(heated oxygen sensor,
heater, heated oxygen sensor
circuit)
- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
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2005 HIGHLANDER REPAIR MANUAL (RM1144U)
Result:
A/F sensor reacts in accordance with increase and decrease of injection volume:
+25 % " rich output: Less than 3.0 V
-12.5 % " lean output: More than 3.35 V
Heated oxygen sensor reacts in accordance with increase and decrease of injection volume:
+25 % " rich output: More than 0.55 V
-12.5 % " lean output: Less than 0.4 V
NOTICE:
The A/F sensor output has a few seconds of delay and the heated oxygen sensor output has about
20 seconds of delay at maximum.
The following A/F CONTROL procedure enables a technician to check and graph the voltage outputs of both
the A/F sensor and the heated oxygen sensor.
For displaying the graph, enter ºACTIVE TEST / A/F CONTROL / USER DATAº, select ºAFS B1S1 and O2S
B1S2º by pressing ºYESº and push ºENTERº. Then press ºF4º.
HINT:
Read freeze frame data using the hand-held tester or the OBD II scan tool. Freeze frame data records the
engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help deter-
mine if the vehicle was running or stopped, 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.

A81695
E8
ECM
O1B-
OX1B
HT1B
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2005 HIGHLANDER REPAIR MANUAL (RM1144U)
1 CHECK OTHER DTC OUTPUT
(a) Read the DTC using the hand-held tester or the OBD II scan tool.
Result:
Display (DTC Output)Proceed to
P0138 is outputA
P0137 is outputB
P0136 is outputC
HINT:
If any other codes besides P0136, P0137 and/or P138 are output, perform the troubleshooting for those
codes first.
B Go to step 9
C Go to step 6
A
2 READ VALUE OF HAND-HELD TESTER OR OBD II SCAN TOOL (OUTPUT
VOLTAGE OF HEATED OXYGEN SENSOR)
(a) Connect the hand-held tester or the OBD II scan tool to the DLC3.
(b) Turn ON the ignition switch. Push the hand-held tester or the OBD II scan tool main switch ON.
(c) Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / O2S B1S2.
(d) Run the engine at idle.
(e) Read the output voltage of the heated oxygen sensor during idling.
Heated oxygen sensor output voltageProceed to
More than 1.2 VA
Less than 1.0 VB
B READ OUTPUT DTC
A
3 CHECK WIRE HARNESS (CHECK FOR SHORT)
(a) Turn the ignition switch OFF and wait for 5 minutes.
(b) Disconnect the E8 ECM connector.
(c) Measure the resistance of the wire harness side connec-
tors.
Standard:
Tester ConnectionSpecified Condition
E8-21 (HT1B) - E8-29 (OX1B)10 kW or higher
E8-21 (HT1B) - E8-2 (O1B-)10 kW or higher
OK REPLACE ECM (See page 10-9)
NG