• | 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 +140°C (-38° to +284°F) Varies with ambient temperature. | |||
IAT Sensor Signal | 141°C (286°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. |
• | DTCs P0112, P0113, P0116, P0117, P0118, P0119, P0125, and P0128 are not set. |
• | The engine coolant temperature (ECT) at engine start is less than 65°C (149°F). |
• | The ECT is greater than 75°C (167°F). |
• | The vehicle speed is less than 10 km/h (6.3 mph). |
• | DTC P0111 runs continuously once the above conditions are met for greater than 2 seconds. |
• | Before the ECM can report DTC P0111 failed, DTC P0101 must run and pass. |
• | DTCs P0112, P0113, P0116, P0117, P0118, P0119, P0125 and P0128 are not set. |
• | The ECT at engine start is less than 65°C (149°F) |
• | The vehicle speed is greater than 60 km/h (37.4 mph). |
• | The MAF is between 11-42 g/s. |
• | Decel fuel cut-off (DFCO) is not active. |
• | DTC P0111 runs continuously once the above conditions are met for greater than 2 seconds. |
• | The engine run time is greater than 3 minutes. |
• | The engine is idling for greater than 10 seconds. |
• | The DTCs runs continuously once the above conditions are met. |
The ECM detects that the IAT increased less than 4°C (7°F) during the idle test. The condition exists for a total of 16 seconds or 4 events of greater than 4 seconds each. Or the ECM detects that the IAT decreased less than 4°C (7°F) during the cruise test. The condition exists for a total of 28 seconds or 7 events of greater than 4 seconds each.
The ECM detects that the intake air temperature is greater than 132°C (270°F) for greater than 4 seconds or a cumulative of 30 seconds.
The ECM detects that the intake air temperature is less than -42°C (-43°F) and remains steady within 3°C (5°F) during a cumulative air flow of greater than 999 grams. The scan tool is limited to -40°C (-40°F), so the diagnostic procedure uses -39°C (-38°F) to determine if there is an IAT condition. The condition exists for greater than 4 seconds or a cumulative of 30 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 may set a DTC. |
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
⇒ | If the IAT parameter fluctuates greater than 3°C (5°F) while moving the related harnesses and connectors, repair the condition as necessary. |
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 warmer than the specified value, test the signal circuit terminal D for a short to ground. If the circuit/connections test normal, replace the 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 less 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 Resistance vs Temperature is not within 5 percent, replace the MAF/IAT sensor. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Engine Control Module Replacement for engine control module replacement, setup, and programming |