Cummins ISX12 CM2250 (2010-12) Fault Code: 629 PID: 314 SPN: 1176 FMI: 18 Turbocharger 1 Compressor Inlet Pressure- Data Valid But Below Normal Operating Range- Moderately Severe Level

Circuit Description
The ECM calculates a differential pressure across the turbocharger using the intake manifold pressure sensor and crankcase pressure sensor.

Component Location
The intake manifold pressure sensor is located in the air intake horn. The crankcase pressure sensor is mounted to the crankcase breather filter housing.

Conditions for Running the Diagnostics
This diagnostic runs continuously when the engine is operating.

Conditions for Setting the Fault Codes
The calculated differential pressure across the turbocharger is greater than a threshold.

Action Taken When the Fault Code is Active
The ECM illuminates the amber CHECK ENGINE lamp immediately when the diagnostic runs and fails.

Conditions for Clearing the Fault Code
To validate the repair, start the engine and let it idle for 1 minute.

The fault code status displayed by INSITE? electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
The ECM will turn off the amber CHECK ENGINE lamp after the diagnostic runs and passes.
The ?Reset All Faults? command in INSITE? electronic service tool can be used to clear active and inactive faults.

Shop Talk
Possible causes of this fault code include:

Plugged or restricted air filter plugged
Restricted crankcase breather filter plugged
Restricted crankcase breather plumbing.

Possible Cause:
1) Intake Manifold temperature/pressure sensor failure
2) ECM calibration