P0112

P0112-INTAKE AIR TEMPERATURE SENSOR CIRCUIT LOW

For a complete wiring diagram, refer to the Wiring Information.





Theory of Operation

Intake Air Temperature Sensor performance looks at the outputs of three temperature sensors and compares them under cold start conditions. Following a start to run delay time, the outputs of the ambient, engine coolant and intake air temperature sensors will be compared. If the engine coolant and ambient air temperature sensors agree and the intake air temperature does not agree, the intake air temperature sensor is declared as irrational. If declared irrational a second comparison will be done after a short drive cycle. The IAT Sensor is a variable resistor that functions as a normal two wire 5 volt sensor. The PCM supplies a 5 volt reference and a ground to the sensors low reference signal circuit.

- When Monitored:
With the ignition on and the battery voltage greater than 10.4 Volts.

- Set Condition:
The Powertrain Control Module (PCM) detects that the Intake Air Temperature (IAT) Sensor input voltage is below the minimum acceptable value.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

Diagnostic Test

1. DTC IS ACTIVE
1. Turn the ignition on.
2. Using the scan tool, select View DTCs.

Is the status Active for this DTC?

Yes

- Go To 2

No

- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test.

2. INTAKE AIR TEMPERATURE SENSOR
1. Turn the ignition off.
2. Disconnect the Intake Air Temperature Sensor harness connector.
3. Turn the ignition on.
4. Using the scan tool, select View DTCs.

Is the P0113-INTAKE AIR TEMPERATURE SENSOR CIRCUIT HIGH DTC active or pending with the harness disconnected?

Yes

- Replace the Intake Air Temperature Sensor. Removal.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 3

3. CHECK THE (K21) IAT SIGNAL CIRCUIT FOR A SHORT TO GROUND




1. Turn the ignition off.
2. Disconnect the Powertrain Control Module (PCM) C2 harness connector.
3. Measure the resistance between ground and the (K21) IAT Signal circuit at the Intake Air Temperature Sensor harness connector.

Is the resistance above 10k Ohms?

Yes

- Go To 4

No

- Repair the (K21) IAT Signal circuit for a short to ground.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

4. CHECK FOR THE (K21) IAT SIGNAL CIRCUIT SHORTED TO THE (K915) SENSOR GROUND CIRCUIT




1. Measure the resistance between the (K21) IAT Signal circuit and the (K915) Sensor Ground circuit in the IAT Sensor harness connector.

Is the resistance above 10k Ohms?

Yes

- Go To 5

No

- Repair the (K21) IAT Signal circuit for a short to the (K915) Sensor Ground circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

5. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Intake Air Temperature Sensor and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals.
4. Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.
5. Look for the data to change or for the DTC to reset during the wiggle test.
6. Perform any Technical Service Bulletins that may apply.

Were any problems found?

Yes

- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Replace and program the Powertrain Control Module (PCM). Powertrain Control Module - Removal.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.