CM2150 Electronic Control System – FAULT CODE 555

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Overview

ISB and QSB3.3 CM2150 – Crankcase Pressure Sensor Circuit SMALL | MEDIUM | LARGE

Circuit Description

The pressure inside the crankcase filter 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.

Component Location

The crankcase pressure sensor is located near the crankcase ventilation filter. Use the following procedure for a detailed component location view.Refer to Procedure 100-002 in Section F.

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 calibrated value.

Action Taken When the Fault Code is Active

• The ECM illuminates the amber CHECK ENGINE light when the crankcase pressure limit is exceeded.

Conditions for Clearing the Fault Code

The ECM will turn off the amber CHECK ENGINE light as soon as the crankcase pressure drops below a calibrated value.

Shop Talk

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, recalibrate the ECM. Use the following procedure in the corresponding Troubleshooting and Repair Manual for the engine being serviced.Refer to Procedure 019-032 in Section 19.

Possible causes of this fault code include:

• Crankcase ventilation filter needs to be replaced
• Crankcase pressure sensor damage
• Malfunctioning or misassembled closed crankcase ventilation valve
• Frozen, plugged, or restricted crankcase ventilation hose
• Plugged or restricted crankcase ventilation hose
• Plugged or restricted crankcase ventilation oil drain tube or check valve
• Plugged or restricted crankcase breather tube (Rear Engine Mounted Crankcase Ventilation Filter)
• High air intake restriction.

Depending on the breather system used, the crankcase ventilation filter will be located:

• On top of the rocker lever cover, between the rocker lever cover and the crankcase ventilation filter cover.
• At the rear of the engine, encased in an external crankcase ventilation filter housing that mounts to the flywheel housing.

Both systems are closed crankcase breather systems, meaning the crankcase gases are vented into the intake system at the inlet to the turbocharger compressor.

It is important to check for plugged or restricted hoses, tubes, check valves, and filters in extreme cold ambient temperatures.

If Fault Code 555 becomes active due to a plugged filter before the maintenance interval is reached or the filter plugs frequently, see the High Blowby (Crankcase Gases (Blowby) Excessive) troubleshooting symptom tree.

Refer to Troubleshooting Fault Code t05-555