Toyota Tundra. Manual — part 1167
Fig. 66: Identifying D8 MAF Meter Connector Terminals
OK : REPLACE ECM (See REMOVAL )
DTC P0111 INTAKE AIR TEMPERATURE SENSOR GRADIENT TOO HIGH
DESCRIPTION
Fig. 67: Intake Air Temperature Graph
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 is low, the resistance of the thermistor increases. When the temperature is high, the resistance
drops. These variations in resistance are transmitted to the ECM as voltage changes (See Fig. 67).
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.
DTC TROUBLE DETECTION CONDITION CHART
DTC
No.
DTC Detection Condition
Trouble Area
When either condition below is met:
1. The intake air temperature rise is large, from the previous trip warm-up to Mass air flow
2008 Toyota Tundra
2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra
MONITOR DESCRIPTION
The ECM performs OBD II monitoring based on the values from the intake air temperature sensor. If there is no
change of the sensor value within the normal range, 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 engine is started (short
soak or long soak).
MONITOR STRATEGY
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
All:
TYPICAL ENABLING CONDITIONS
After engine stop:
TYPICAL ENABLING CONDITIONS
P0111
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.
meter
Related DTCs
P0111: Intake air temperature sensor rationality (After engine
stop)
P0111: Intake air temperature sensor rationality (After cold
engine start)
Required Sensors/Components (Main) Intake Air Temperature (IAT) sensor
Required Sensors/Components
(Related)
-
Frequency of Operation
Once per driving cycle
Duration
5 hours or more
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 circuit
OK
ECT change since engine stop
Less than -40°C (-40°F)
ECT before engine stop
70°C (158°F) or more
Time that MAF is low before engine stop
2100 sec.
Accumulated MAF amount before engine stop
4963 g or more
2008 Toyota Tundra
2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra
After cold engine start:
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
After engine stop:
TYPICAL MALFUNCTION THRESHOLDS
After cold engine start:
TYPICAL MALFUNCTION THRESHOLDS
WIRING DIAGRAM
Refer to DTC P0102 .
INSPECTION PROCEDURE
HINT:
Read freeze frame data using the Techstream. Freeze frame data records the engine condition when
malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was
moving or stationary, 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 ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0111)
a. Connect the Techstream to the DLC3.
b. Turn the ignition switch ON.
c. Turn the Techstream ON.
d. Enter the following menus: Powertrain/Engine and ECT/Trouble Codes.
Key-off duration
30 minutes
Key-off duration
5 hours
Time after engine start
10 seconds or more
ECT sensor circuit
OK
ECT
70°C (158°F) or more
Accumulated MAF amount
4963 g or more
Either 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 (2°F)
IAT change
Less than 1°C (2°F)
2008 Toyota Tundra
2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra
e. Read the DTCs.
Result
RESULT CHART
HINT:
If any DTCs other than P0111 are output, troubleshoot those DTCs first.
B : REPLACE MASS AIR FLOW METER (See REMOVAL )
A : GO TO DTC CHART (See DIAGNOSTIC TROUBLE CODE CHART )
DTC P0115 ENGINE COOLANT TEMPERATURE CIRCUIT MALFUNCTION; DTC P0117 ENGINE
COOLANT TEMPERATURE CIRCUIT LOW INPUT; DTC P0118 ENGINE COOLANT
TEMPERATURE CIRCUIT HIGH INPUT
DESCRIPTION
A thermistor, whose resistance value varies according to the ECT, is built into the Engine Coolant Temperature
(ECT) sensor.
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 (176°F) by the ECM. Fail-safe mode continues until a pass condition is detected.
DTC TROUBLE DETECTION CONDITION CHART
Display (DTC Output) Proceed To
P0111 and other DTCs
A
P0111
B
DTC
No.
DTC Detection Condition
Trouble Area
P0115
Open or short in ECT sensor circuit for 0.5 seconds (1 trip
detection logic)
Open or short in ECT sensor
circuit
ECT sensor
ECM
P0117
Short in ECT sensor circuit for 0.5 seconds (1 trip detection
logic)
Short in ECT sensor
ECT sensor
ECM
2008 Toyota Tundra
2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra
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