Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSCHEVROLET1999EXPRESS 1/2 TON VAN V6-4.3L VIN WREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTCOMPUTERS AND CONTROL SYSTEMSDESCRIPTION AND OPERATIONINTAKE AIR TEMPERATURE (IAT) SENSOR
1999 Chevrolet Express 1/2 Ton Van V6-4.3L VIN W
Intake Air Temperature (IAT) Sensor
1999 Chevrolet Express 1/2 Ton Van V6-4.3L VIN WSECTION Intake Air Temperature (IAT) Sensor
Intake Air Temperature (IAT) Sensor:
The Intake Air Temperature (IAT) sensor is a thermistor which changes the value based on the temperature of the air entering the engine. A low temperature produces a high resistance (100,000 ohms at -40°C/-40 °F). A high temperature causes a low resistance (70 ohms at 130°C/266°F). The VCM supplies a 5.0 volt signal to the sensor through a resistor in the VCM and measures the voltage. The voltage will be high when the incoming air is cold, and low when the air is hot. By measuring the voltage, the VCM calculates the incoming air temperature. The IAT sensor signal is used in order to adjust the spark timing according to the incoming air density.
The scan tool displays the temperature of the air entering the engine, which should read close to the ambient air temperature when the engine is cold. The temperature should rise as the underhood temperature increases. If the engine has not been run for several hours (overnight), the IAT sensor temperature and the engine coolant temperature should read close to each other. If the VCM detects a malfunction in the IAT sensor circuit, the following DTCs will set:
^ DTC P0112 circuit low
^ DTC P0113 circuit high
^ DTC P1111 circuit intermittent high
^ DTC P1112 circuit intermittent low
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.