P0112

P0112-INTAKE AIR TEMPERATURE (IAT) SENSOR VOLTAGE TOO LOW





For complete wiring diagrams refer to Diagrams/Electrical.


- When Monitored:

With the ignition on and battery voltage greater than 10.4 volts.

- Set Condition:

The circuit voltage to the ECM falls below a calibrated threshold for a certain period of time.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.


1. INTAKE AIR TEMP SENSOR OUT OF SPECIFICATION

Disconnect the Intake Air Temperature sensor harness connector.

Check connectors - Clean/repair as necessary.

Measure the resistance of the Intake Air Temp sensor.

Is the resistance between 300 and 90k ohms?

Yes

- Go To2

No

- Replace the Intake Air temperature sensor/MAP sensor.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

2. INTERMITTENT CONDITION

Reconnect the circuit.

Turn the ignition on.

With the scan tool, erase DTCs.

With the scan tool, read DTCs.

Did the DTC reappear?

Yes

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition

No

- Go To3

3. (K21) SIGNAL CIRCUIT SHORTED TO GROUND CIRCUIT





Turn the ignition off.

Disconnect the ECM harness connector.

Check connectors - Clean/repair as necessary.

Measure the resistance between the engine ground and the temperature sensor (K21) signal circuit at the sensor harness connector.

Is the resistance more than 100 k ohms?

Yes

- Go To4

No

- Repair or replace the engine wiring harness.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

4. WIRING HARNESS SHORTED





Measure the resistance between the (K21) signal circuit and all other circuits at the ECM harness connector.

Is the resistance more than 100 k ohms?

Yes

- Go To5

No

- Repair or replace the shorted wiring harness.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

5. (F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO (K916) RETURN CIRCUIT





Reconnect the ECM harness connector connected.

Turn the ignition on.

Measure the voltage between the (F855) 5-volt supply circuit and the (K916) return circuit the sensor harness connector.

Is the voltage between 4.5 and 5.5 volts?

Yes

- Go To7

No

- Go To6

6. (F855) 5-VOLT SUPPLY CIRCUIT OPEN





Turn the ignition off.

Disconnect the ECM harness connector.

Measure the voltage at the (F855) 5-volt supply circuit of the sensor harness connector.

Is the voltage between 4.5 and 5.5 volts?

Yes

- Repair the open (F855) 5-volt supply circuit.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To7

7. ECM

Reconnect the ECM harness connector.

Reconnect the intake air temp sensor harness connector.

Turn the ignition on.

While monitoring with scan tool, disconnect the temperature sensor

Did the DTC P0113 set?

Yes

- Clear DTC's, repair complete.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Replace the ECM.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test