TOYOTA SIENNA 2007 Service Repair Manual

2GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEMES–135
ES
C
A
(a) Disconnect the M6 Mass Air Flow (MAF) meter
connector.
(b) Connect terminals THA and E2 of the MAF meter wire
harness side connector.
(c) Connect the intelligent tester to the DLC3.
(d) Turn the ignition switch to the ON position.
(e) Turn the tester on.
(f) Select the following menu items: DIAGNOSIS /
ENHANCED OBD II / DATA LIST / PRIMARY / INTAKE
AIR.
(g) Read the value displayed on the tester.
Standard:
140
C (284F) or higher
(h) Reconnect the MAF meter connector.
OK
NGCHECK FOR INTERMITTENT PROBLEMS
2READ VALUE OF INTELLIGENT TESTER (CHECK FOR OPEN IN WIRE HARNESS)
A140711E04
REPLACE MASS AIR FLOW METER (See
page ES-504)

ES–1362GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEM
ES
(a) Disconnect the M6 MAF meter connector.
(b) Disconnect the E9 ECM connector.
(c) Measure the resistance according to the value(s) in the
table below.
Standard resistance:
Check for open
Check for short
(d) Reconnect the MAF meter connector.
(e) Reconnect the ECM connector.
OK
NG
(a) Disconnect the M6 MAF meter connector.
(b) Connect the intelligent tester to the DLC3.
(c) Turn the ignition switch to the ON position.
(d) Turn the tester on.
(e) Select the following menu items: DIAGNOSIS /
ENHANCED OBD II / DATA LIST / PRIMARY / INTAKE
AIR.
(f) Read the value displayed on the tester.
Standard:
-40
C (-40F)
(g) Reconnect the MAF meter connector.
OK
NG
3CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)
A140709E05
Tester Connection Specified Condition
THA (E9-22) - THA (M6-1) Below 1
E2 (E9-28) - E2 (M6-2) Below 1
Tester Connection Specified Condition
THA (E9-22) or THA (M6-1) - Body ground 10 k
or higher
E2 (E9-28) or E2 (M6-2) - Body ground 10 k
or higher
REPAIR OR REPLACE HARNESS OR
CONNECTOR (MASS AIR FLOW METER -
ECM)
REPLACE ECM (See page ES-498)
4READ VALUE OF INTELLIGENT TESTER (CHECK FOR SHORT IN WIRE HARNESS)
A084869E47
REPLACE MASS AIR FLOW METER

2GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEMES–137
ES
(a) Disconnect the M6 MAF meter connector.
(b) Disconnect the E9 ECM connector.
(c) Measure the resistance according to the value(s) in the
table below.
Standard resistance
(d) Reconnect the MAF meter connector.
(e) Reconnect the ECM connector.
OK
NG
5CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)
A140709E06
Tester Connection Specified Condition
THA (E9-22) or THA (M6-1) - Body ground 10 k
or higher
REPAIR OR REPLACE HARNESS OR
CONNECTOR (MASS AIR FLOW METER -
ECM)
REPLACE ECM (See page ES-498)

ES–1382GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEM
ES
DESCRIPTION
The Intake Air Temperature (IAT) sensor, mounted on the Mass Air Flow (MAF) meter, monitors the IAT.
The IAT sensor has a built-in thermistor with a resistance that varies according to the temperature of the
intake air. When the IAT becomes low, the resistance of the thermistor increases. When the temperature
becomes high, the resistance drops. These variations in resistance are transmitted to the ECM as voltage
changes (see Fig. 1).
The IAT sensor is powered by a 5 V supply from the THA terminal of the ECM, via resistor R.
Resistor R and the IAT sensor are connected in series. When the resistance value of the IAT sensor
changes according to changes in the IAT, the voltage at terminal THA also varies. Based on this signal,
the ECM increases the fuel injection volume when the engine is cold to improve driveability.
MONITOR DESCRIPTION
The ECM performs OBD II monitoring based on the values from the intake air temperature sensor. If there
is no change in the sensor value, the ECM will not be able to perform OBD II monitoring or will
misdiagnose that there is a malfunction in the sensor. The ECM detects the stuck intake air temperature
sensor value by performing monitoring after the ignition switch is turned off or the ignition is started (short
soak or long soak).
MONITOR STRATEGY
DTC P0111Intake Air Temperature Sensor Gradient Too
High
DTC No. DTC Detection Condition Trouble Area
P01111. The intake air temperature rise becomes larger,
from the previous trip warm-up to the following
trip.(2 trip detection logic)
2. When the change in the intake air temperature after
engine start is less than the threshold value.Mass air flow meter assembly
Related DTCsP0111: Intake air temperature sensor rationality (After engine stop)
P0111: Intake air temperature sensor rationality (After cold engine
start)
A067628E13

2GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEMES–139
ES
TYPICAL ENABLING CONDITIONS
All:
After engine stop:
After cold engine start:
TYPICAL MALFUNCTION THRESHOLDS
After engine stop:
After cold engine start:
WIRING DIAGRAM
Refer to DTC P0110 (See page ES-126).
INSPECTION PROCEDURE
(a) Connect the intelligent tester to the DLC3.
(b) Turn the ignition switch to the ON position.
(c) Turn the tester on.
(d) Enter the following menus: DIAGNOSIS / ENHANCED
OBD II / DTC INFO / CURRENT CODES.
Required Sensors / Components (Main) Intake Air Temperature (IAT) sensor
Required Sensors / Components (Sub) -
Frequency of Operation Once per driving cycle
Duration 5 hours
MIL Operation 2 driving cycles
Sequence of Operation None
Monitor runs whenever following DTCs are not present None
Time after engine start 10 seconds or more
Battery voltage 10.5 V or more
ECT sensor OK
ECT change since engine stopped Less than 180
C (356F)
ECT before engine stop 70
C (158F) or more
Time that MAF is low before engine stop 70 minutes
Accumulated MAF amount before engine stop 3774 g or more
Key-off duration 30 minutes
Key-off duration 5 hours
Time after engine start 10 seconds or more
ECT sensor OK
ECT 70
C (158F) or more
Accumulated MAF amount 3774 g or more
One of the following conditions 1 or 2 is met: -
1. Duration while engine load is low 120 seconds or more
2. Duration while engine load is high 10 seconds or more
IAT change Less than 1
C (2F)
IAT change Less than 1
C (2F)
1CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0111)

ES–1402GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEM
ES
(e) Read the DTCs.
Result
HINT:
If any DTCs other than P0111 are output, troubleshoot
those DTCs first.
B
A
Display (DTC Output) Proceed to
P0111 and other DTCs A
P 0 111 B
REPLACE MASS AIR FLOW METER (See
page ES-504)
GO TO DTC CHART (See page ES-56)

2GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEMES–141
ES
DESCRIPTION
A thermistor is built into the Engine Coolant Temperature (ECT) sensor, of which the resistance value
varies according to the ECT.
The structure of the sensor and its connection to the ECM are the same as those of the Intake Air
Temperature (IAT) sensor.
HINT:
When any of DTCs P0115, P0117 and P0118 are set, the ECM enters fail-safe mode. During fail-safe
mode, the ECT is estimated to be 80
C (176F) by the ECM. Fail-safe mode continues until a pass
condition is detected.
HINT:
When any of these DTCs are set, check the ECT by selecting the following menu items on the intelligent
tester: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / COOLANT TEMP.
MONITOR DESCRIPTION
The Engine Coolant Temperature (ECT) sensor is used to monitor the ECT. The ECT sensor has a
thermistor with a resistance that varies according to the temperature of the engine coolant. When the
coolant temperature becomes low, the resistance in the thermistor increases. When the temperature
becomes high, the resistance drops.
These variations in resistance are reflected in the voltage output from the sensor. The ECM monitors the
sensor voltage and uses this value to calculate the ECT. When the sensor output voltage deviates from
the normal operating range, the ECM interprets this as a fault in the ECT sensor and sets a DTC.
Example:
If the sensor voltage output is -40
C (-40F) for 0.5 seconds or more, the ECM determines that there is an
open in the ECT sensor circuit, and sets DTC P0118. Conversely, if the voltage output is more than 140
C
(284
F) for 0.5 seconds or more, the ECM determines that there is a short in the sensor circuit, and sets
DTC P0117.
If the malfunction is not repaired successfully, a DTC is set 0.5 seconds after the engine is next started.
MONITOR STRATEGY
DTC P0115 Engine Coolant Temperature Circuit
DTC P0117 Engine Coolant Temperature Circuit Low Input
DTC P0118 Engine Coolant Temperature Circuit High Input
DTC No. Proceed to DTC Detection Condition Trouble Area
P0115 Step 1Open or short in Engine Coolant Temperature
(ECT) sensor circuit for 0.5 seconds (1 trip
detection logic)• Open or short in ECT sensor circuit
• ECT sensor
•ECM
P0117 Step 4Short in Engine Coolant Temperature (ECT)
sensor circuit for 0.5 seconds (1 trip detection
logic)• Short in ECT sensor circuit
• ECT sensor
•ECM
P0118 Step 2Open in Engine Coolant Temperature (ECT)
sensor circuit for 0.5 seconds (1 trip detection
logic)• Open in ECT sensor circuit
• ECT sensor
•ECM
Temperature Displayed Malfunctions
-40
C (-40F) Open circuit
140
C (284F) or higher Short circuit
Related DTCsP0115: Engine coolant temperature sensor open/short (Fluctuating)
P0117: Engine coolant temperature sensor short (Low electrical voltage)
P0118: Engine coolant temperature sensor open (High electrical voltage)

ES–1422GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEM
ES
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
P0115:
P0117:
P0118:
COMPONENT OPERATING RANGE
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
• If other DTCs relating to different systems that have terminal E2 as the ground terminal are output
simultaneously, terminal E2 may have an open circuit.
Required Sensors / Components (Main) Engine coolant temperature sensor
Required Sensors / Components (Related) -
Frequency of Operation Continuous
Duration 0.5 seconds
MIL Operation Immediate
Sequence of Operation None
The monitor will run whenever these DTCs are not
presentNone
Engine coolant temperature sensor voltage Less than 0.14 V or more than 4.91 V
Engine coolant temperature sensor voltage Less than 0.14 V [More than 140
C (284F)]
Engine coolant temperature sensor voltage More than 4.91 V [Less than -40
C (-40F)]
Engine coolant temperature sensor voltage 0.14 V to 4.91 V [-40 to 140
C (-40 to 284F)]
A072925E48

2GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEMES–143
ES
• Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition
information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame
data can be helpful in determining whether the vehicle was running or stopped, whether the engine
was warmed up or not, whether the air-fuel ratio was lean or rich, as well as other data recorded at the
time of a malfunction.
(a) Connect the intelligent tester to the DLC3.
(b) Turn the ignition switch to the ON position.
(c) Turn the tester on.
(d) Select the following menu items: DIAGNOSIS /
ENHANCED OBD II / DATA LIST / PRIMARY /
COOLANT TEMP.
(e) Read the value displayed on the tester.
Standard:
Between 80
C and 97C (176F and 207F) with
warm engine.
Result
HINT:
• If there is an open circuit, the intelligent tester
indicates -40
C (-40F).
• If there is a short circuit, the intelligent tester indicates
140
C (284F) or higher.
B
C
A
1READ VALUE OF INTELLIGENT TESTER (ENGINE COOLANT TEMPERATURE)
Temperature Displayed Proceed to
-40
C (-40F) A
140
C (284F) or higher B
Between 80
C and 97C (176F and 207F) C
Go to step 4
CHECK FOR INTERMITTENT PROBLEMS

ES–1442GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEM
ES
(a) Disconnect the E12 Engine Coolant Temperature (ECT)
sensor connector.
(b) Connect terminals 1 and 2 of the ECT sensor connector
on the wire harness side.
(c) Connect the intelligent tester to the DLC3.
(d) Turn the ignition switch to the ON position.
(e) Turn the tester on.
(f) Select the following menu items: DIAGNOSIS /
ENHANCED OBD II / DATA LIST / PRIMARY /
COOLANT TEMP.
(g) Read the value displayed on the tester.
Standard:
140
C (284F) or higher
(h) Reconnect the ECT sensor connector.
OK
NG
(a) Disconnect the E12 ECT sensor connector.
(b) Disconnect the E9 ECM connector.
(c) Measure the resistance according to the value(s) in the
table below.
Standard resistance
(d) Reconnect the ECM connector.
(e) Reconnect the ECT connector.
OK
2READ VALUE OF INTELLIGENT TESTER (CHECK FOR OPEN IN WIRE HARNESS)
A114610E05
REPLACE ENGINE COOLANT
TEMPERATURE SENSOR (See page ES-516)
3CHECK HARNESS AND CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR -
ECM)
A162492E01
Tester Connection Specified Condition
THW (E9-21) - E12-2 Below 1
E2 (E9-28) - E12-1 Below 1
REPAIR OR REPLACE HARNESS OR
CONNECTOR (ENGINE COOLANT
TEMPERATURE SENSOR - ECM)