John Deere Error Code ECU 000111.01 — What It Means and How to Fix It

Applies to: All modern JD tractors with electronic engines and coolant level sensors, Most common on 6R, 7R, 8R, 9R series and S-Series combines

STOP — Low coolant at high temperature. Shut down and cool before opening anything.

Shut down after idling for 2 minutes. Wait at least 15 minutes before opening any cooling system component. NEVER open the radiator cap while hot.

JD ECU 000111.01John DeereManually verified

Coolant Level Low at High Coolant Temperature

The coolant level switch has triggered at the same time as elevated coolant temperature. You're low on coolant while the engine is already hot. This combination dramatically increases the risk of engine damage.

Repair difficulty

DIY — Basic tools

Repair time

20 min

Dealer cost

$150-400

What to check first

  1. 1

    Idle for 2-3 minutes then shut down — let the engine cool for at least 15 minutes

  2. 2

    Check the coolant overflow reservoir — if empty, you have a significant leak

  3. 3

    Once cool, top up with correct coolant (Cool-Gard II 50/50 mix). If no coolant available, clean water will get you home.

Likely causes

  1. 1

    Actual coolant leak (hose, clamp, water pump weep hole, radiator)— Most likely

    DIY

    Look for puddles under the tractor and wet spots around all hose connections.

  2. 2

    Air lock in cooling system after service— Possible

    DIY

    Common on dual-temp systems (6020/6030/7020/7030 series). See bleeding procedure in operator's manual.

  3. 3

    Head gasket failure— Less common

    Shop

    Coolant disappearing without visible external leak, milky oil, bubbles in reservoir. Major repair.

  4. 4

    Coolant level sensor fault— Less common

    DIY

    If coolant level is actually fine but sensor triggers, the sensor or its wiring may be faulty.

  5. 5

    Radiator cap not holding pressure— Possible

    DIY

    A worn cap lowers the boiling point — coolant boils off through the overflow.

Parts needed

Tools needed

  • Coolant (or clean water for emergency)
  • Funnel
  • Flashlight (for leak inspection)
  • Infrared temperature gun (helpful)

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Pro tip

Keep the coolant overflow tank filled to the MAX line at all times. On dual-temperature systems, always bleed the system after any coolant work — an air lock can cause false level readings.

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