FC 2311 — Electronic Fuel Injection Control Valve Circuit – Condition Exists (SPN 633 FMI 31) — Cummins ISX15

Diagnostic reference for Cummins ISX15 (2010–2017) CM2250/CM2350 with XPI high-pressure common rail.

Updated October 15, 2026

What it means

The fuel pump actuator (fuel control valve) is not controlling as expected. On the ISX15 XPI system this maps to SPN 633 FMI 31 and points to the fuel pump actuator, its wiring or fuel supply condition.¹

Most likely causes

1. Fuel pump actuator (fuel control valve) performance or internal fault on the XPI high-pressure pump — The actuator is not achieving commanded rail pressure or response; typical on this platform for SPN 633 FMI 31.¹
2. Wiring/connector fault to the fuel pump actuator — Chafed, corroded or loose harness/connector at the pump actuator can cause a condition-exists fault.¹
3. Low fuel supply / restriction causing actuator compensation limits — Electric lift pump, filters or air ingress can force the actuator out of expected control range; XPI pump actuator issues are commonly linked to fuel supply problems on this platform.¹

How to diagnose

1. Verify active/mature status and snapshot data (engine speed, load, rail pressure actual vs desired) to confirm the condition exists under the reported operating point.
2. Inspect fuel pump actuator harness and connector at the XPI pump for chafing, corrosion, moisture or loose terminals; check ECM connector pins for fretting.
3. Review recent companion codes for fuel supply: lift pump circuit faults (e.g., FC 2266/2265), water-in-fuel (FC 418), filter differential pressure high (FC 2372). Supply faults can drive actuator condition-exists.
4. Check fuel supply integrity: lift pump operation, filter condition, and signs of air ingress; compare rail pressure actual vs desired at idle and load.
5. If no wiring or supply issue is found and the code persists with rail pressure deviation, the fuel pump actuator is suspect. Diagnosis of high-pressure fuel components should be performed by qualified service following manufacturer safety procedures.
6. Clear codes, perform a controlled road test while monitoring SPN 633 FMI 31, rail pressure control and related fuel system parameters; confirm the fault does not return.

Common mistake to avoid

Installing an ISX15/X15 fuel pump without the correct timing tool. A mis-timed pump can cause gear-train noise, poor fuel delivery and, in bad cases, serious engine damage. Source: Apex Industries — ISX15/X15 fuel pump timing tool.

Parts and tools you may need

• Diagnostic scan tool capable of Cummins FC/SPN-FMI and live data
• Digital multimeter
• Inspection light and mirror
• Basic hand tools for connector and harness inspection

Tools you’ll need

• Cummins Insite diagnostic software — Reads SPN 633 FMI 31 and live rail pressure actual vs desired to confirm actuator control deviation under load.
• digital multimeter — Checks actuator harness continuity, resistance and reference/return voltages to rule out wiring faults.
• fuel pressure test kit — Measures lift pump supply pressure and verifies no restriction or air ingress that forces actuator compensation.
• borescope — Inspects XPI pump actuator connector and harness routing for chafing, corrosion or moisture without disassembly.

Rough cost and difficulty

Typical US independent-shop figures; labor runs about $140–$200 per hour (dealers charge more). Confirm the diagnosis before buying parts.

When to see a pro

High-pressure fuel system diagnosis involves hazardous pressures. If rail pressure control is abnormal or the fault persists after supply and wiring checks, have the vehicle inspected by a Cummins-certified technician. Do not service high-pressure components without proper training and equipment.

Check for recalls

Recalls are tied to your truck’s VIN, so check yours directly: enter the VIN at NHTSA’s recall lookup. Open safety recalls are repaired free at a dealer.

Sources