P0112-INTAKE AIR TEMPERATURE SENSOR CIRCUIT LOW

For a complete wiring diagram Refer to Section 8W.

When Monitored:
With the ignition on and battery voltage greater than 10.4 volts.
Set Condition:
When the Inlet Air Temp Sensor Signal circuit voltage is less than .078 volt for more than 2.8 seconds. One trip failure. Three good trips to clear the MIL.

Possible Causes

(K21) IAT SIGNAL SHORTED TO GROUND

(K21) IAT SIGNAL SHORTED TO THE (K900) SENSOR GROUND CIRCUIT

INTAKE AIR TEMPERATURE SENSOR

PCM

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

1.IAT SENSOR VOLTAGE BELOW 0.078 OF A VOLT

Is the voltage below 0.078 of a volt?

Yes

Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

2.IAT SENSOR

Is the voltage above 0.05 of a volt?

Yes

Replace the Intake Air Temperature Sensor.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

3.(K21) IAT SIGNAL SHORTED TO GROUND

Is the resistance below 100 ohms?

Yes

Repair the short to ground in the (K21) IAT Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

4.(K21) IAT SIGNAL SHORTED TO THE (K900) SENSOR GROUND CIRCUIT

Is the resistance below 100 ohms?

Yes

Repair the short between the (K900) Sensor ground circuit and the (K21) IAT Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

5.PCM

NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

Were there any problems found?

Yes

Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

Replace and program the Powertrain Control Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)