Rational E40 Error Code

What does Rational E40 mean?

E40 (Service 40) on Rational SelfCookingCenter and iCombi units indicates the Care pump is not delivering enough Care solution into the steam generator during a CleanJet + Care cycle. The control monitors Care tab dissolution and flow; when the expected volume is not detected, the oven aborts the cycle and posts the fault so the next clean cannot run until the supply path is restored.

Symptoms

• CleanJet + Care cycle aborts and displays Service 40 or E40.
• Care tab container shows little or no consumption after a run.
• Steam generator is not being dosed, leading to scale buildup over time.
• Unit blocks further automatic cleaning until the fault is cleared.

Common causes

• Care pump is blocked, airlocked, or has failed mechanically.
• Kinked, pinched, or detached dosing hose between the Care canister and pump.
• Empty or incorrectly seated Care tab container.
• Low incoming water pressure or clogged water filter starving the dosing circuit.
• Defective pump driver or wiring on the I/O board.

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Diagnostic steps

1. Verify Care supply and tab container

   Confirm the Care tab container is full, seated correctly, and the pickup tube reaches the fluid. Prime a new container if the oven has run dry.

2. Inspect the dosing hose

   Trace the hose from the Care canister to the pump and into the steam generator. Straighten any kinks, reseat fittings, and replace a hose that is cracked or collapsed.

3. Check water supply

   Verify inlet pressure meets the nameplate spec and clean or replace the water filter. Inadequate water starves the Care dilution circuit and trips Service 40.

4. Test the Care pump

   Manually actuate the Care pump in service mode and watch for fluid movement. A pump that hums without pumping is airlocked or seized and must be replaced.

5. Clear the fault with a rinse run

   After the mechanical fix, run a successful rinse/CleanJet cycle so the control confirms dosing is restored and clears the stored fault.

6. Inspect control board if fault persists

   If the pump is good and plumbing is clear, check pump drive voltage at the I/O board harness; replace the board if drive output is missing.

When to call a professional

Call a RATIONAL-authorized service technician if the fault returns after you replace the Care pump, if the CleanJet cycle still aborts after verifying water pressure and hoses, or if there is visible leaking around the steam generator. Pump replacement involves draining the steam generator and working around live mains wiring on the I/O board, and an incorrect repair can cause scale damage to the heating elements that voids the warranty.