CM850 Electronic Control System – FAULT CODE 2215 (ISC/QSC/ISL/QSL Automotive, Industrial, or Marine Application)

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Overview

Fuel Flow Diagram SMALL | MEDIUM | LARGE

Circuit Description

The pressure control loop relies on fuel pressure supplied to the high-pressure pump by the fuel gear pump. The electronic control module (ECM) monitors rail fuel pressure and engine operating conditions and changes the flow command to maintain the proper rail fuel pressure. Changes to the flow command result in opening (or closing) of the fuel pump actuator to supply more (or less) fuel to the high-pressure pump.

The fuel flow circuit includes, in the following order:

• OEM fuel tank
• OEM fuel supply line
• Water stripping fuel filter (10 micron, water stripping, suction side fuel filter)
• Engine mounted OEM fuel connection
• Fuel supply tube to ECM cooling plate
• ECM cooling plate
• Fuel supply tube to the low-pressure gear pump
• Fuel supply tube to the pressure-side fuel filter
• Primary fuel filter (3 micron pressure-side fuel filter)
• Fuel supply tube to the high-pressure pump
• High-pressure pump
• High-pressure system (including fuel rail and fuel rail pressure relief valve), injectors, and high-pressure lines.

Component Location

The high-pressure fuel pump is mounted to the gear housing on the intake side of the engine. Refer to Procedure 100-002 in Section E.

Shop Talk

If the engine will not start and Fault Code 2215 becomes active during cranking, but no speed sensor fault codes exist, monitor the fuel rail pressure with INSITE™ electronic service tool. If the rail pressure is low, check the following:

• Fuel system prime (make sure there is fuel in the tanks and the system is primed)
• Fuel lift pump pressure; Use the procedure in the Troubleshooting and Repair Manual, ISC, ISCe, QSC8.3, ISL, ISLe3, ISLe4 and QSL9 Engines, Bulletin 4021418: Refer to Procedure 005-045 in Section 5.
• Fuel gear pump pressure; Use the procedure in the Troubleshooting and Repair Manual, ISC, ISCe, QSC8.3, ISL, ISLe3, ISLe4 and QSL9 Engines, Bulletin 4021418: Refer to Procedure 005-025 in Section 5.

If the gear pump pressure is OK, test for system leakage:

• High-pressure pump leakage; Use the procedure in the Troubleshooting and Repair Manual, ISC, ISCe, QSC8.3, ISL, ISLe3, ISLe4 and QSL9 Engines, Bulletin 4021418: Refer to Procedure 005-227 in Section 5.
• Injector leakage; Use the procedure in the Troubleshooting and Repair Manual, ISC, ISCe, QSC8.3, ISL, ISLe3, ISLe4 and QSL9 Engines, Bulletin 4021418: Refer to Procedure 006-026 in Section 6.
• Fuel rail pressure relief valve.

If Fault Code 2215 is inactive and there are no existing performance complaints, it is possible the vehicle was run out of fuel or the engine was not primed following fuel filter replacement. Clear the inactive fault code.

Fault Code 2215 sets when the engine is running and measured rail fuel rail pressure remains at least 10 Mpa [1450 psi] less than commanded pressure. Once detected, Fault Code 2215 will remain active until the engine is turned off or until the measured fuel rail pressure matches the commanded fuel rail pressure. When a condition exists that causes Fault Code 2215 to become active, it is typical for the fault code to become active when the engine is heavily loaded and become inactive when the engine is lightly loaded.

When Fault Code 2215 occurs, the fuel system has lost its ability to maintain fuel rail pressure. Causes of this fault include:

• Excessive fuel inlet restriction
• Fuel filter plugging
• Air in the fuel system
• Fuel gear pump output low
• Fuel gear pump pressure regulator sticking or leaking
• High-pressure pump capacity decay (high leakage to drain from the high-pressure pump)
• Fuel rail pressure relief valve leaks to drain
• Fuel rail pressure relief valve opens at too low a pressure
• Injector fuel circuit leaks to drain
• Pressure sensor reads more than 10 Mpa [1450 psi] lower than actual pressure.

Intermittent ECM power supply connections can cause Fault Code 2215. If the engine is running with an active Fault Code 2215 and Fault Codes 449 or 2311 are not present, check the ECM power supply for intermittent connections. Fault Code 1117 can also be active if this fault condition exists.

Inactive Fault Code:

Troubleshooting inactive Fault Code 2215 can be very difficult. The fault code must be active for any of the outlined procedures in which the engine is operated during the test. For engines with high counts of inactive Fault Code 2215, operate the engine on a chassis dynamometer or a diagnostic road test to duplicate the fault code. The most common causes of intermittent Fault Code 2215 that are difficult to create are leaking high-pressure connectors that only leak when the engine and the fuel are hot, and intermittent fuel supply restrictions, such as debris floating in the fuel tank. Check the High Pressure Connector (HPC) and connector torque and torque to specification if necessary. Operate the engine on a chassis dynamometer or conduct a diagnostic road test to duplicate the fault code.

Refer to Troubleshooting Fault Code t05-2215