Crankcase Pressure – Data Valid but Above Normal Operational Range
– Most Severe Level
|Fault Code: 556
Crankcase Pressure – Data Valid but Above Normal Operational Range –
Engine power derate.
ISX – Crankcase Pressure Sensor Circuit
ISM – Crankcase Pressure Sensor Circuit
The pressure inside the crankcase is measured by the crankcase pressure sensor. When the crankcase pressure sensor determines that the crankcase pressure is higher than normal, this fault code is logged.
The crankcase pressure sensor is located in the crankcase filter. The crankcase filter is located on the fuel system side of the engine. Use the following procedure for a detailed component location view. Refer to Procedure 100-002 in Section E.
Conditions for Running the Diagnostics
This diagnostic runs continuously when the engine speed is greater than 500 rpm.
Conditions for Setting the Fault Codes
The ECM detects that the crankcase pressure is greater than a calibratible limit.
Action Taken When the Fault Code is Active
- The ECM illuminates the red STOP ENGINE light when the crankcase pressure limit is exceeded.
- The engine torque output will be reduced to protect the engine from excessive crankcase pressure.
Conditions for Clearing the Fault Code
The ECM will turn off the red STOP ENGINE light as soon as the crankcase pressure drops below a calibratible limit.
Verify the electronic control module (ECM) calibration is correct. Check the calibration revision history found on QuickServe™ Online for applicable fixes to the calibration stored in the ECM. If necessary, calibrate the ECM. Refer to Procedure 019-032 in Section 19.
Possible causes of this fault code include:
- Crankcase filter needs to be replaced.
- Frozen crankcase breather filter.
- Frozen inlet tube to the crankcase breather filter housing.
- Frozen outlet tube from the crankcase breather filter housing.
- Frozen inside the crankcase breather filter housing.
If the crankcase filter is being replaced frequently for this fault code, refer to the Crankcase Coalescing Filter – Frequent Replacement troubleshooting symptom tree.
- For ISM engines, refer to the ISM, ISMe, and QSM11 Service Manual, Bulletin 3666322.
- For ISX engines, refer to the Signature™, ISX and QSX15 Service Manual, Bulletin 3666329.