Cummins fault code · DEF (diesel exhaust fluid) system

Cummins fault code 6562

DEF Tank Level Sensor: root cause not known

J1939 SPN1761
FMI11
LampNo lamp
SystemDEF

What it means

Cummins' description: Aftertreatment 1 Diesel Exhaust Fluid Tank Level Sensor - Root Cause Not Known.

SPN 1761 is Aftertreatment 1 Diesel Exhaust Fluid Tank Level. FMI 11 means the ECM detected a fault in this system but can't pin down the exact type. Further testing is needed.

DEF is sprayed into the exhaust ahead of the SCR catalyst to break down NOx. The system includes the tank, level and temperature sensors, a quality sensor, heaters for cold weather, a pump or dosing unit, lines and the doser.

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

The DEF level warning is on and the truck runs normally. Topping off with fresh DEF clears it.

Yellow

Schedule a repair

Amber lamp or a DEF quality or dosing code that comes back after filling. Get it checked soon. If left alone, the system will start counting down toward a derate.

Red

Stop and get help

Blinking lamp with a derate countdown, or the truck is already limited to low speed. That's an EPA inducement. It won't fix itself and it can leave a truck stuck at 5 mph.

Common causes

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

  • DEF tank low or empty
  • Contaminated, diluted or old DEF (water, coolant, diesel, or DEF older than about a year)
  • Crystallized DEF clogging the doser, lines or filter
  • Weak pump or blocked DEF filter
  • Frozen DEF with a heater not working

What you can check before calling

  • Check the DEF level and top off with fresh, sealed DEF
  • Look for white crystal buildup around the doser, lines and tank
  • If DEF was recently added, think about whether it could have been mixed with water or something else
  • Note whether the code shows up only in cold weather

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: DEF warning lights and derate: what diesel drivers need to know.

Engines and sources

Listed by Cummins for: QSB 6.7, QSL 9, QSX 15, QSB 4.5, QSF 3.8 (With SCR). 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 6562 mean?

Cummins fault code 6562 is J1939 SPN 1761 FMI 11: Aftertreatment 1 Diesel Exhaust Fluid Tank Level Sensor - Root Cause Not Known. In plain terms: def tank level sensor: root cause not known.

Can I keep driving with Cummins code 6562?

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 6562?

SPN 1761 identifies the part or system (Aftertreatment 1 Diesel Exhaust Fluid Tank Level). FMI 11 describes the type of failure: root cause not known.

What usually causes Cummins code 6562?

The most common causes are: dEF tank low or empty; contaminated, diluted or old DEF (water, coolant, diesel, or DEF older than about a year); crystallized DEF clogging the doser, lines or filter.

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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