P0112

P0112-INTAKE AIR TEMPERATURE SENSOR 1 CIRCUIT LOW





For a complete wiring diagram refer to the Wiring Information Electrical Diagrams. Electrical Diagrams

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 ECM supplies 5 volts to the intake manifold temperature signal circuit. The ECM 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 4 consecutive drive cycles.

- When Monitored:
The ECM 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 volts for 5 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 30 seconds.
5. Turn the ignition on.
6. With the scan tool, read DTCs.

Did the DTC reset?

Yes

- Go To 2

No

- Refer to the INTERMITTENT CONDITION - DIESEL (Diagnostic Procedure). Intermittent Condition Test

2. 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 POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test

3. (K21) INTAKE MANIFOLD TEMPERATURE SENSOR SIGNAL CIRCUIT SHORTED TO GROUND




1. Disconnect the ECM 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 short to ground in the (K21) Intake Manifold Temperature Sensor Signal circuit.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test

No

- Go To 4

4. (K21) INTAKE MANIFOLD TEMPERATURE SENSOR SIGNAL CIRCUIT SHORTED TO (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 POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test

No

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