2001 TOYOTA HIGHLANDER o2 sensor
[x] Cancel search: o2 sensorPage 1644 of 2572
A90346
Reference
Heater
Sensor
Duty
Control ECM
From
Battery
EFI NO. 1
FuseEFI Relay
+B HT
EFI NO. 2
Fuse
MREL OX1B HT1B Heated Oxygen Sensor
OB1- OX E1 05-76
- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
266 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
DTC P0037 OXYGEN SENSOR HEATER CONTROL
CIRCUIT LOW (BANK 1 SENSOR 2)
DTC P0038 OXYGEN SENSOR HEATER CONTROL
CIRCUIT HIGH (BANK 1 SENSOR 2)
CIRCUIT DESCRIPTION
Refer to DTC P0136 on page 05-1 18.
HINT:
The ECM provides a pulse width a modulated control circuit to adjust current through the heater. The oxygen
sensor heater circuit uses a relay on the +B side of the circuit.
DTC No.DTC Detection ConditionTrouble Area
P0037
Heater current of less than 0.3 A when the heater operates
with +B greater than 10.5 V
(1 trip detection logic)Open or short in heater circuit of heated oxygen sensor
Heated oxygen sensor heater
EFI relay
ECM
P0038Heater current exceeds 2 A when heater operates
(1 trip detection logic)Same as DTC No. P0037
HINT:
Sensor 2 is the sensor farthest away from the engine assembly.
MONITOR DESCRIPTION
The sensing portion of the heated oxygen sensor has a zirconia element that is used to detect oxygen con-
centration in the exhaust. If the zirconia element is at the proper temperature and the difference of the oxy-
gen concentration between the inside and outside surface of the sensor is large, the zirconia element will
generate 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 sen-
sor. 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 A when the heater is OFF.
Similarly, the ECM will set a low current DTC if the current is less than 0.25 A when the heater is ON.
05ETE-05
Page 1645 of 2572
- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
05-77
267 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
MONITOR STRATEGY
Related DTCsP0037: HO2S heater range check (Low current)
P0038: HO2S heater range check (High current)
Required sensors / components (Main)Heated oxygen sensor (HO2S) heater
Required sensors / components (Related)Vehicle speed sensor (VSS)
Frequency of operationContinuous
Duration0.3 sec.
MIL operationImmediate
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
All:
The monitor will run whenever these DTCs are not presentSee page 05-16
P0037:
Battery voltage10.5 V or more
EngineRunning
StarterOFF
Intrusive heatingNot operated
P0038 (Case 1):
Battery voltage10.5 V or more
EngineRunning
StarterOFF
Intrusive heatingNot operated
P0038 (Case 2):
Battery voltage10.5 V or more
All heater is turned OFF and intrusive heating is operated
when the following conditions are metCondition 1 and 2
1. HeaterON
2. Heater current2 A or more
TYPICAL MALFUNCTION THRESHOLDS
P0037:
HO2S heater current intrusive heatingLess than 0.3 A
P0038 (Case 1):
HO2S heater current2 A or more
P0038 (Case 2):
HO2S heater current intrusive heatingMore than 2 A
COMPONENT OPERATING RANGE
HO2S heater current0.4 to 1 A (when engine is idle, warmed-up and battery voltage is 11 to 14 V)
Page 1646 of 2572
A80018
H10
Heated Oxygen Sensor
+B HT
E1 OX
05-78
- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
268 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
MONITOR RESULT
Refer to page 05-24 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 (see page 05-26).
TID (Test Identification Data) is assigned to each emissions-related component.
TLT (Test Limit Type):
If TLT is 0, the component is malfunctioning when the test value is higher than the test limit.
If TLT is 1, the component is malfunctioning when the test value is lower than the test limit.
CID (Component Identification Data) is assigned to each test value.
Unit Conversion is used to calculate the test value indicated on generic OBD ll scan tools.
TID $04: HO2S heater
TLTCIDUnit ConversionDescription of Test DataDescription of Test Limit
1$02Multiply by 0.000076
(A)Maximum HO2S heater current
(Bank 1 Sensor 2)Malfunction threshold for HO2S heater
WIRING DIAGRAM
Refer to DTC P0136 on page 05-1 18.
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 INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)
(a) Disconnect the H10 heated oxygen sensor connector.
(b) Measure the resistance of the heated oxygen sensor ter-
minals.
Standard:
Tester ConnectionConditionSpecified Condition
H10-2 (HT) - H10-1 (+B)20C (68F)11 to 16 W
H10-2 (HT) - H10-1 (+B)800C (1,472F)23 to 32 W
NG REPLACE HEATED OXYGEN SENSOR
OK
Page 1648 of 2572
A81695
A80019A91528
Wire Harness Side
E8
ECM
H10
Heated Oxygen Sensor
HT +B
OX E1 HT1B
A80019
A90291A91529
Wire Harness Side
H10
Heated Oxygen Sensor
HT
+B
OX
E1
EFI RelayEngine Room J/B
05-80
- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
270 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
4 CHECK WIRE HARNESS (ECM - HEATED OXYGEN SENSOR, HEATED OXYGEN
SENSOR - EFI RELAY)
(a) Check the wire harness between the ECM and heated ox-
ygen sensor.
(1) Disconnect the E8 ECM connector.
(2) Disconnect the H10 heated oxygen sensor connec-
tor.
(3) Measure the resistance of the wire harness side
connectors.
Standard:
Tester ConnectionSpecified Condition
H10-2 (HT) - E8-21 (HT1B)Below 1 W
H10-2 (HT) or E8-21 (HT1B) - Body ground10 kW or higher
(b) Check the wire harness between the heated oxygen sen-
sor and EFI relay.
(1) Disconnect the H10 heated oxygen sensor connec-
tor.
(2) Remove the EFI relay from the engine room J/B.
(3) Measure the resistance of the wire harness side
connectors.
Standard:
Tester ConnectionSpecified Condition
H10-1 (+B) - J/B EFI relay terminal 3Below 1 W
H10-1 (+B) or J/B EFI relay terminal 3 -Body ground10 kW or higher
NG REPAIR OR REPLACE HARNESS AND
CONNECTOR
OK
REPLACE ECM (See page 10-9)
Page 1650 of 2572
A96746
Fuel Tank Canister
Vacuum Pump: OFF Pressure Sensor 0.02 Inch Orifice
Pump Module
Operation A: Atmospheric Pressure Measurement
Vent Valve: OFF (vent)
Operation D: Purge VSV monitor Operation B, E: 0.02 Inch Leak Pressure Measurement
Negative
Pressure Atmospheric
Pressure
Operation C: EVAP System Pressure Measurement
Air Filter
Purge VSV: OFFOFF (vent)
ON
OFF
OFF
ON
ON (closed)ON
ON
ON (closed)
- DIAGNOSTICSSFI SYSTEM (2AZ-FE)(From August, 2004)
05-191
381 Author: Date:
MONITOR DESCRIPTION
5 hours* after the ignition switch is turned OFF, the electric vacuum pump creates negative pressure (vacu-
um) in the EVAP (Evaporative Emission) system. The ECM monitors for leaks and actuator malfunctions
based on the EVAP pressure.
HINT:
*: If the engine coolant temperature is not below 35C (95F) after 5 hours after the ignition switch is turned
off, the monitor check starts 2 hours later. If it is still not below 35C (95F) 7 hours after the ignition switch
is turned off, the monitor check starts 2.5 hours later.
SequenceOperationsDescriptionsDuration
-ECM activationActivated by soak timer, 5 hours (7 or 9.5 hours) after ignition switch turned to OFF.-
AAtmospheric pressure
measurement
Vent valve turned OFF (vent) and EVAP system pressure measured by ECM in order to
register atmospheric pressure.
If EVAP pressure is not between 70 kPa and 110 kPa (525 mmHg and 825 mmHg), ECM
cancels EVAP system monitor.
10 seconds
B
First 0.02 inch leak
pressure measure-
mentIn order to determine 0.02 inch leak pressure standard, vacuum pump creates negative pres-
sure (vacuum) through 0.02 inch orifice and then ECM checks if vacuum pump and vent
valve operate normally.
60 seconds
CEVAP system pres-
sure measurement
Vent valve turned ON (closed) to shut EVAP system.
Negative pressure (vacuum) created in EVAP system, and EVAP system pressure then
measured.
Write down the measured value as it will be used in the leak check.
If EVAP pressure does not stabilize within 15 minutes, ECM cancels EVAP system monitor.
15 minutes*
DPurge VSV monitorPurge VSV opened and then EVAP system pressure measured by ECM.
Large increase indicates normal.10 seconds
E
Second 0.02 inch leak
pressure measure-
mentLeak check is performed after second 0.02 inch leak pressure standard is measured.
If stabilized system pressure higher than second 0.02 inch leak pressure standard, ECM
determines that EVAP system leaking.
60 seconds
FFinal checkAtmospheric pressure measured and then monitoring result recorded by ECM.-
* If only a small amount of fuel is in the fuel tank, it takes longer for the EVAP pressure to stabilize.
Page 1652 of 2572
- DIAGNOSTICSSFI SYSTEM (2AZ-FE)(From August, 2004)
05-193
383 Author: Date:
OBD II MONITOR SPECIFICATIONS
Monitor Strategy
Required Sensors/ComponentsPump module
Frequency of OperationOnce per driving cycle
DurationWithin 15 minutes (varies with amount of fuel in tank)
MIL Operation2 driving cycles
Sequence of OperationNone
Typical Enabling Conditions
The monitor will run whenever these DTCs are not presentSee page 05-16.
EVAP key-off monitor runs when all of the following condi-
tions met:-
Atmospheric pressure525 to 825 mmHg (70 to 110 kPa)
Battery voltage10.5 V or more
Vehicle speedBelow 4 km/h (2.5 mph)
Ignition switchOFF
Engine conditionNot running
Time after engine stopped5 hours
FTP sensor malfunction (P0450, P0452, P0453)Not detected
Purge VSVNot operated by scan tool
Vent valveNot operated by scan tool
Leak detection pumpNot operated by scan tool
Both of the following conditions are met before IG switch
OFF:Condition 1 and 2
1. Duration that vehicle is driven5 min. or more
2. Purge flowExecuted
ECT4.4 to 35C (40 to 95F)
IAT4.4 to 35C (40 to 95F)
Example of re-start time
First time7 hours
Second time9 hours and 30 min.
Key-of f monitor sequence: 1 to 8
1. Atmospheric pressure
Next sequence is run if following condition met-
Atmospheric pressure change for 10 sec.Within 2.25 mmHg (0.3 kPa) for 1 sec.
2. First reference pressure
Next sequence is run if all of following conditions metCondition 1, 2 and 3
1. FTP when 4 sec. after reference pressure measurement-7.5 mmHg (-1 kPa) or less
2. Reference pressure-36.47 to -7.93 mmHg (-4.85 to -1.057 kPa)
3. Reference pressureSaturated
3. Vent valve stuck closed check
Next sequence is run if following condition met-
FTP change for 10 sec. after vent valve ON (closed)2.25 mmHg (0.3 kPa) or more
4. Vacuum introduction and leak
Next sequence is run if both of following conditions metCondition 1 and 2
1. Vacuum introduction timeWithin 15 min.
2. FTPFTP was saturated
5. Purge VSV stuck closed check
Next sequence is run if following condition met-
FTP change for 10 sec. after purge VSV ON (open)2.25 mmHg (0.3 kPa) or more
Page 1655 of 2572
A80089
AB B+
Power Transistor
Platinum Hot Wire
(Heater)
Output
Voltage
Temperature
Sensor
Platinum Hot Wire (Heater)
Temperature Sensor
- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
05-81
271 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
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, changing 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 air flow 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
P0100When MAF meter circuit has an open or a short for more than
3 secondsOpen or short in MAF meter circuit
MAF meter
ECM
P0102When MAF meter circuit has an open for more than 3 secondsSame as DTC No. P0100
P0103When MAF meter circuit has a short for more than 3 secondsSame as DTC No. P0100
HINT:
After confirming DTC P0100, P0102 or P0103, use the hand-held tester or the OBD II scan tool to confirm
the MAF ratio from the ALL menu (to reach the ALL menu: DIAGNOSIS / ENHANCED OBD II / DATA LIST
/ ALL).
Air Flow Value (g/s)Malfunction
Approximately 0.0Open in MAF meter power source circuit
Open or short in VG circuit
271.0 or moreOpen in EVG circuit
05ESV-05
Page 1656 of 2572
05-82
- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
272 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
MONITOR DESCRIPTION
If there is a defect in the sensor, or an open or short circuit, the voltage level will deviate from the normal
operating range. The ECM interprets this deviation as a defect in the MAF meter and sets a DTC.
Example:
The sensor voltage output is less than 0.2 V or more than 4.9 V and either condition continues for more than
3 seconds.
MONITOR STRATEGY
Related DTCs
P0100: MAF meter range check (Chattering)
P0102: MAF meter range check(Low voltage)
P0103: MAF meter range check (High voltage)
Required sensors / components (Main)MAF Meter
Required sensors / components (Related)CKP (Crank shaft position) sensor
Frequency of operationContinuous
Duration3 sec.
MIL operationImmediate: Engine RPM is less than 4,000 rpm
2 driving cycles: Engine RPM is 4,000 rpm or more
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
The monitor will run whenever these DTCs are not presentSee page 05-16
TYPICAL MALFUNCTION THRESHOLDS
P0100:
MAF meter voltageLess than 0.2 V, or more than 4.9 V
P0102:
MAF meter voltageLess than 0.2 V
P0103:
MAF meter voltageMore than 4.9 V
COMPONENT OPERATING RANGE
MAF meter voltageBetween 0.4 and 2.2 V