P0112

P0112-INTAKE AIR TEMPERATURE SENSOR 1 CIRCUIT LOW





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

Theory of Operation

The Intake Manifold Temperature Sensor is located on the intake manifold and is used to measure the temperature of the air in the intake manifold of the engine. The Powertrain Control Module (PCM) supplies 5 volts to the intake manifold temperature signal circuit. The PCM monitors the change in voltage caused by changes in the resistance of the sensor to determine the intake manifold temperature. The MIL lamp is illuminated immediately when the diagnostic runs and fails. During this time the customer may notice periods of white smoke as well as the fan running more often. The MIL lamp is turned off once the diagnostic runs and passes in four consecutive drive cycles.

- When Monitored:
The PCM monitors the change in signal voltage and converts this to a temperature value.

- Set Condition:
The (K21) Intake Manifold Temperature Sensor Signal circuit drops below 0.25 of a Volt for five seconds.





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

1. ACTIVE DTC
1. Turn the ignition on.
2. With the scan tool, record all Freeze frame data.
3. With the scan tool, erase DTCs.
4. Turn the ignition off for 75 seconds.
5. Turn the ignition on.
6. With the scan tool, read DTCs.

Did the DTC reset?

Yes

- Go To 2

No

- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test

2. CHECK THE INTAKE MANIFOLD TEMPERATURE SENSOR
1. Turn the ignition off.
2. Disconnect the Intake Manifold Temperature Sensor harness connector.

NOTE: Check connectors - Clean/repair as necessary.

3. Measure the resistance across the Intake Manifold Temperature Sensor.

Is the resistance between 300 and 90k Ohms?

Yes

- Go To 3

No

- Replace the Intake Manifold Temperature Sensor.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

3. CHECK THE (K21) INTAKE MANIFOLD TEMPERATURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND




1. Disconnect the PCM C1 harness connector.

NOTE: Check connectors - Clean/repair as necessary.

2. Measure the resistance between ground and the (K21) Intake Manifold Temperature Sensor Signal circuit at the Intake Manifold Temperature Sensor harness connector.

Is the resistance below 10k Ohms?

Yes

- Repair the (K21) Intake Manifold Temperature Sensor Signal circuit for a short to ground.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 4

4. CHECK FOR THE (K21) INTAKE MANIFOLD TEMPERATURE SENSOR SIGNAL CIRCUIT SHORTED TO THE (K914) SENSOR GROUND CIRCUIT




1. Measure the resistance between the (K21) Intake Manifold Temperature Sensor Signal circuit and the (K914) Intake Manifold Temperature Sensor Ground circuit at the Intake Manifold Temperature Sensor harness connector.

Is the resistance below 10k Ohms?

Yes

- Repair the short between the (K21) Intake Manifold Temperature Sensor Signal circuit and the (K914) Intake Manifold Temperature Sensor Ground circuit.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Replace the Powertrain Control Module.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.