Cummins fault code · Engine control and configuration

Cummins fault code 5215

Engine Boost Curve Selection: erratic or intermittent signal

J1939 SPN520791
FMI2
LampAmber warning lamp
SystemEngine control and configuration

What it means

Cummins' description: Engine Boost Curve Selection - Data erratic, intermittent or incorrect.

SPN 520791 is Engine Boost Curve Selection. FMI 2 means the signal is jumping around, dropping in and out, or doesn't make sense compared to other readings.

This code relates to an engine control feature or configuration setting. The meaning depends on how the ECM is programmed for your truck or equipment.

What the lamp means

An amber (yellow) warning lamp means the engine can usually keep running, but the fault should be repaired soon, ideally the same day.

How serious is it?

Green, yellow, red: three ways this can look

The same code can be a quick fix or a reason to shut down. Match your situation to the closest example.

Green

Keep an eye on it

An informational code with no lamp and the engine runs normally.

Yellow

Schedule a repair

Amber lamp or the code returns with a drivability change. Have it diagnosed.

Red

Stop and get help

Red lamp, stalling or a no-start. Don't drive it until it's diagnosed.

Common causes

The sensor reading itself is out of range or the condition is real, so look at the system:

  • ECM setting or calibration doesn't match the equipment
  • Condition reported by another module

What you can check before calling

  • Note what the engine was doing when the code set
  • Check for recent ECM programming or added equipment

Clearing the code without fixing the cause usually brings it right back, and on emissions systems it can restart derate timers.

Engines and sources

Listed by Cummins for: QSX 15, QSG 12. Cummins uses the same fault code numbers across its electronic engines, including on-highway models like the ISB/B6.7, ISL/L9 and ISX/X15, though not every code applies to every engine or software level. Source: Cummins Tier 4 Fault Codes. Always confirm with Cummins service information (QuickServe) for your engine serial number.

Look up another code

Cummins fault code (like 1922), J1939 SPN and FMI (like SPN 3251 FMI 0), or an OBD-II code (like P0420).

Questions

What does Cummins fault code 5215 mean?

Cummins fault code 5215 is J1939 SPN 520791 FMI 2: Engine Boost Curve Selection - Data erratic, intermittent or incorrect. In plain terms: engine boost curve selection: erratic or intermittent signal.

Can I keep driving with Cummins code 5215?

Usually for a short time, if the engine runs normally and no other warnings are on. Get it diagnosed soon, because many amber codes lead to a derate if ignored. Look at the green, yellow and red examples on this page to judge your situation.

What is the SPN and FMI for Cummins code 5215?

SPN 520791 identifies the part or system (Engine Boost Curve Selection). FMI 2 describes the type of failure: erratic or intermittent signal.

What usually causes Cummins code 5215?

The most common causes are: eCM setting or calibration doesn't match the equipment; condition reported by another module.

Diesel down in the Midlands?

We work on Cummins-powered pickups, vans and medium-duty trucks across Lexington, Columbia and the Midlands, on site at your yard or roadside.

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