Cummins fault code · Cooling fan

Cummins fault code 6467

Fan Speed: reading above normal (least severe)

J1939 SPN1639
FMI15
LampNo lamp
SystemCooling fan

What it means

Cummins' description: Fan Speed - Data Valid but Above Normal Operational Range - Least Severe Level.

SPN 1639 is Fan Speed. FMI 15 means the value is somewhat above normal. It's the mildest 'high' level, often an early warning.

The cooling fan pulls air through the radiator and charge air cooler. On most trucks it's controlled by a fan clutch the ECM switches on and off, and some have speed sensors or variable pitch blades.

What the lamp means

This code normally doesn't turn on a dash lamp. It's logged in the ECM for a technician to see, and often explains another active code.

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

A fan code that set once with normal engine temperatures.

Yellow

Schedule a repair

Temperatures creep up at idle or with A/C on, or the code keeps returning. Get it checked before summer heat finds it for you.

Red

Stop and get help

Engine overheating because the fan isn't engaging. Shut it down and let it cool before driving.

Common causes

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

  • Fan clutch worn and slipping
  • Air leak to an air-operated fan clutch
  • Fan stuck on or off

What you can check before calling

  • Listen for the fan engaging when the engine is hot or the A/C is on
  • Look for damaged wiring or air lines at the fan clutch
  • Watch whether temperature climbs at idle or in traffic

Clearing the code without fixing the cause usually brings it right back, and on emissions systems it can restart derate timers. For the bigger picture, read our guide: Car overheating: what to do right now, and what's causing it.

Engines and sources

Listed by Cummins for: QSB 6.7, QSL 9, QSX 15, QSB 4.5, QSF 3.8, 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 6467 mean?

Cummins fault code 6467 is J1939 SPN 1639 FMI 15: Fan Speed - Data Valid but Above Normal Operational Range - Least Severe Level. In plain terms: fan speed: reading above normal (least severe).

Can I keep driving with Cummins code 6467?

Usually, yes. This code doesn't normally turn on a lamp by itself, but check for other active codes that might be more serious. Look at the green, yellow and red examples on this page to judge your situation.

What is the SPN and FMI for Cummins code 6467?

SPN 1639 identifies the part or system (Fan Speed). FMI 15 describes the type of failure: reading above normal (least severe).

What usually causes Cummins code 6467?

The most common causes are: fan clutch worn and slipping; air leak to an air-operated fan clutch; fan stuck on or off.

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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