• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
IAT Sensor Signal | P0112 | P0111, P0113 | P0113* | P0111 |
Low Reference | -- | P0111, P0113 | P0113* | P0111 |
* Internal ECM or sensor damage may occur if the circuit is shorted to B+ |
Circuit | Short to Ground | Open | Short to Voltage |
---|---|---|---|
Operating Conditions: Engine operating in Closed Loop. Parameter Normal Range: -39 to +134°C (-38 to +274°F) Varies with ambient temperature. | |||
IAT Sensor Signal | 135°C (275°F) | -40°C (-40°F) | -40°C (-40°F)* |
Low Reference | -- | -40°C (-40°F) | -40°C (-40°F)* |
* Internal ECM or sensor damage may occur if the circuit is shorted to B+ |
The intake air temperature (IAT) sensor is an integral part of the mass air flow (MAF) sensor. The IAT sensor is a variable resistor that measures the temperature of the intake air. The engine control module (ECM) supplies 5 volts to the IAT signal circuit and supplies a ground to the low reference circuit.
The following table illustrates the difference between temperature, resistance, and voltage:
IAT | IAT Resistance | IAT Signal Voltage |
---|---|---|
Cold | High | High |
Warm | Low | Low |
• | Before the ECM can report DTC P0111 failed, DTC P0101 must run and pass. |
• | DTC P0112, P0113, P0116, P0117, P0118, P0119, or P0128 is not set. |
• | The engine coolant temperature (ECT) at engine start is colder than 110°C (230°F). |
• | The ECT is warmer than 66°C (151°F). |
• | The vehicle speed is less than 11 km/h (7 mph). |
• | The MAF is less than 8 g/s. |
• | DTC P0111 runs continuously once the above conditions are met for approximately 300 seconds, depending on the drive cycle. |
• | Before the ECM can report DTC P0111 failed, DTC P0101 must run and pass. |
• | DTC P0112, P0113, P0116, P0117, P0118, P0119, or P0128 is not set. |
• | The ECT at engine start is colder than 110°C (230°F). |
• | The vehicle speed is greater than 29 km/h (18 mph). |
• | The MAF is between 7-67 g/s. |
• | Decel fuel cut-off (DFCO) is not active. |
• | DTC P0111 runs continuously once the above conditions are met for approximately 300 seconds, depending on the drive cycle. |
• | The vehicle speed is less than 3 mph. |
• | The ECT is warmer than -10°C (14°F). |
• | The MAF is less than 28 g/s. |
• | The DTCs runs continuously once the above conditions are met for greater than 2 seconds. |
The ECM detects that the IAT remains steady within 2°C (4°F) during the idle test. Or, the ECM detects that the IAT decreased less than 2°C (4°F) during the cruise test. The condition exists for greater than 4 seconds or for a cumulative of 30 seconds.
The ECM detects that the IAT sensor voltage is greater than 4.87 volts for greater than 1 second or for a cumulative 10 seconds.
The ECM detects that the IAT sensor voltage is less than 0.21 volts for greater than 1 second or for a cumulative 10 seconds.
DTCs P0111, P0112, and P0113 are Type B DTCs.
DTCs P0111, P0112, and P0113 are Type B DTCs.
• | If the vehicle has sat overnight, the IAT sensor and the ECT sensor values should display within 3°C (5°F). |
• | High resistance on either the IAT sensor signal circuit or the IAT sensor low reference circuit could set a DTC. |
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
Caution: Do NOT use a test lamp to test the continuity of the circuit. Damage to the control module may occur due to excessive current draw.
⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance, or for a short to voltage. If the circuit/connections test normal, replace the ECM. |
⇒ | If greater than the specified value, test the signal circuit for a short to ground. If the circuit/connections test normal, replace the engine control module (ECM). |
Note: If the fuse in the jumper wire opens, the signal circuit is shorted to a voltage and the sensor may be damaged.
⇒ | If colder than the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit/connections test normal, replace the ECM. |
Note: A thermometer can be used to test the sensor off the vehicle.
⇒ | If the not within the specified range, replace the IAT sensor. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for engine control module replacement, setup, and programming |