DTC P0113 Intake Air Temperature (IAT) Sensor Circuit High Voltage. Isuzu S/T Isuzu

For 1990-2009 cars only

Makes 🢒 Isuzu 🢒 1999 🢒 S/T Isuzu - 2WD 🢒 Engine 🢒 Engine Controls - 2.2L 🢒 DTC P0113 Intake Air Temperature (IAT) Sensor Circuit High Voltage

Engine Controls Components
Cell 20: MAP, IAT, TPS and ECT Sensors
OBD II Symbol Description Notice
Powertrain Control Module Connector End Views
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The Intake Air Temperature (IAT) sensor is a thermistor which controls the signal voltage to the PCM. The PCM supplies a 5V reference and a ground to the sensor. When the air is cold, the resistance will be high. Whenever the intake air is warm, the resistance will be low.

Conditions for Running the DTC

•	The engine run time is more than 320 seconds.

•	The engine coolant temperature (ECT) is more than -40°C (-40°F).

•	The vehicle speed sensor indicates that vehicle speed is less than 15 mph (24 km/h).

Conditions for Setting the DTC

The IAT sensor signal voltage indicates that the intake air temperature is less than -40°C (-40°F) for 3 seconds.

Action Taken When the DTC Sets

•	The Malfunction Indicator Lamp (MIL) illuminates after two consecutive ignition cycles with the malfunction present.

•	The PCM records the operating conditions at the time the diagnostic fails. The Freeze Frame and Failure Records buffers stores this information.

•	A history DTC is stored.

•	The PCM will default to 60°C (140°F) for intake air temperature. The scan tool will not show the defaulted value.

Conditions for Clearing the MIL/DTC

•	The malfunction indicator lamp (MIL) will turn OFF after 3 consecutive ignition cycles in which the diagnostic runs without a fault.

•	A history DTC will clear after 40 consecutive warm up cycles without a fault.

•	Use a scan tool to clear the DTCs.

Diagnostic Aids

•	When the vehicle is at ambient temperature, compare the IAT sensor to the ECT sensor. The IAT sensor and the ECT sensor should be relatively close to each other.

•	Use the Temperature vs Resistance Values Table below to evaluate the possibility of a skewed sensor. Refer to Temperature Versus Resistance .

Test Description

The number(s) below refer(s) to the step number(s) on the Diagnostic Table.

The Powertrain OBD System Check prompts you to complete some of the basic checks and to store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data captured when the malfunction occurred. The scan tool stores this data for later reference.

This step simulates a DTC P0112. If the PCM senses the change, the PCM and wiring are OK.

This step will determine if the reason that the PCM did not sense the change was due to the following condition(s):

•	Open ground circuit

•	Short to voltage in the signal circuit

•	Malfunctioning PCM

Reprogram the replacement PCM and perform the crankshaft position system variation learn procedure. Refer to the latest Isuzu Technical Communications System (ITCS) information for PCM programming and the Crankshaft Position System Variation Learn for the crankshaft position system variation learn procedure.

DTC P0113-Intake Air Temperature (IAT) Circuit-High Voltage

Step

Action

Value(s)

Yes

Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

Turn ON the ignition switch leaving the engine OFF.
Install a scan tool.

Is the IAT sensor value less than the specified value?

-30°C (-22°F)

Go to Step 4

Go to Step 3

Review the Freeze Frame data and record the parameters.
Start the engine.
Operate the vehicle within the conditions for setting this DTC as specified in the supporting text.

Is the IAT sensor value less than the specified value?

-30°C (-22°F)

Go to Step 4

Go to Diagnostic Aids

Turn OFF the ignition switch.
Disconnect the IAT sensor electrical connector.
Connect a jumper wire between the following circuits at the IAT sensor electrical connector:

•	IAT sensor signal circuit terminal

•	IAT sensor ground circuit terminal

Turn ON the ignition switch leaving the engine OFF.

Is the IAT sensor value greater than the specified value?

130°C (266°F)

Go to Step 6

Go to Step 5

Connect a jumper wire to the IAT sensor signal circuit terminal to ground.

Is the IAT sensor value greater than the specified value?

130°C (266°F)

Go to Step 7

Go to Step 8

Turn OFF the ignition switch.
Check for poor electrical connections at the IAT sensor electrical connector.
Repair the electrical connections as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

Go to Step 12

Go to Step 10

Turn OFF the ignition switch.
Check for an open in the IAT sensor ground.
Repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

Go to Step 12

Go to Step 9

Turn OFF the ignition switch.
Check for an open in the IAT sensor signal circuit.
Repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

Go to Step 12

Go to Step 9

Check for the following conditions in the PCM electrical connector(s):

•	Poor IAT sensor ground circuit terminal

•	Poor IAT sensor signal circuit terminal

Repair the circuit terminal(s) as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

Go to Step 12

Go to Step 11

Replace the IAT sensor. Refer to the Intake Air Temperature Sensor Replacement .

Is the action complete?

Go to Step 12

Replace the PCM. Refer to the Powertrain Control Module Replacement .

Is the action complete?

Go to Step 12

Using the scan tool, clear the DTCs.
Start the engine.
Idle the engine at the normal operating temperature.
Operate the vehicle within the conditions for setting this DTC as specified in the supporting text.

Does the scan tool indicate that this diagnostic has ran and passed?

Go to Step 13

Go to Step 2

Check to see if any additional DTCs are set.

Does the scan tool display any DTCs that you have not diagnosed?

Go to applicable DTC table

System OK