Technical Description of OBD-II Trouble Code
High Input in Circuit 1 of Intake Air Temperature Sensor
What does that signify?
This diagnostic trouble code (DTC) is a generic powertrain code that is applicable to vehicles equipped with OBD-II. Although it is a generic code, the specific repair steps may vary depending on the make and model of the vehicle.
The powertrain control module (PCM) monitors the temperature of the air entering the engine. The PCM provides a 5 volt reference voltage to the Intake Air Temperature (IAT) sensor.
The IAT is a thermistor that changes its resistance based on temperature. As the temperature increases, the resistance decreases. A low temperature results in a high signal voltage. When the PCM detects a signal voltage higher than 5 volts, it triggers this P0113 check engine light code.
Potential Symptoms
There will likely be no symptoms other than the illumination of the Malfunction Indicator Lamp (MIL – Check Engine Light / Service Engine Soon).
Causes
A code P0113 may indicate that one or more of the following has occurred:
Possible Solutions
First, if you have access to a scan tool, check if there is an IAT reading. If the IAT reading is logical, then the problem is likely intermittent. If the reading is less than -30 degrees, unplug the connector. Install a jumper wire between the harness connector signal and ground circuits. The IAT temperature reading on the scan tool should be at the maximum value. For example, it should be 280 degrees Fahrenheit or higher. If it is, the wiring is fine, and the issue may have been the connection. If it is not, install the jumper wire between the IAT signal circuit and the chassis ground.
If the IAT reading on the scan tool is now at the maximum value, then check for an open in the IAT ground circuit. If you get no reading at all on the scan tool, it is likely that the sensor signal is open or the 5 volt reference is missing. Use a DVOM (digital volt ohm meter) to check for a 5 volt reference. If it is present, then unplug the connector at the PCM and check for continuity on the IAT signal circuit between the PCM connector and the IAT connector.
Other DTCs related to the IAT sensor and circuit: P0095, P0096, P0097, P0098, P0099, P0110, P0111, P0112, P0114, P0127
