DTC P0112/16496: IAT Sensor Circuit Low Input
NOTE:
DTC is set when Intake Air Temperature (IAT) circuit detects a low or high input.
- Ensure ignition is off. Disconnect ECM connector. Connect Test Box (VAG 1598/18) to ECM wiring harness. Terminal assignments of test box are identical to ECM connector. Measure resistance between test box terminals No. 33 and 36. See IAT SENSOR RESISTANCE
table.IAT SENSOR RESISTANCE
Temperature Ohms 86°F (30°C) 1500-2000 176°F (80°C) 275-375 - If resistance is to specification, go to next step. If resistance is not to specification, disconnect IAT sensor connector. Measure resistance between IAT connector terminal No. 1 and test box terminal No. 36. Resistance should be less than 1.5 ohms. If resistance is infinite, check wiring for an open circuit. If resistance is not infinite, check wiring for a short circuit to ground.
- Disconnect IAT sensor. Connect ohmmeter between IAT sensor terminals No. 1 and 2. Cool sensor with a freeze spray. Resistance should increase without interruption. When sensor is heated, resistance should drop. If resistances are not to specification, replace sensor. If resistances are to specification, replace ECM.