Wolf L Series Code CHECKSUM: Power-Up self-check failed

What CHECKSUM means

On Wolf L Series legacy wall ovens with the Invensys control, such as the SO30F/S, DO30U/S or SO36U/S, CHECKSUM appears when the control's self-check failed. The control runs that check at power-up and again when you press the oven OFF key. The oven may not start, may display CHECKSUM at power-up or may shut down after you stop a cycle.

Common causes of CHECKSUM

Control memory data not passing its check
Power interruption during a write
Failing oven controller
Brief supply disturbance at the oven

✓ One safe check you can try

1. Press OFF and let the oven sit for a few minutes. 2. Switch the oven breaker off for one minute and back on. 3. Watch whether CHECKSUM shows again at power-up. 4. If it does, call us. Please do not press keys repeatedly or open the control.

! Why to stop there

A failed self-check points at the controller itself, which is not an owner repair.
Old Invensys controls need careful testing before we recommend replacement.
You receive a written price and approve it before any work.
A 30-day workmanship warranty protects the repair afterward.

Opening a panel yourself does not automatically cancel a manufacturer warranty, but it can cause accidental damage, and some manufacturers set their own service conditions. Check your warranty terms, or ask us, before deciding.

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Other Wall Oven codes

0121Wolf M Series Oven Code 0121: upper right convection relay shorted 0221Wolf M Series Code 0221: Upper Bake Element DLB Shorted 0321Wolf M Series Oven Code 0321: Broil Relay Shorted on the Upper Element 0421Wolf M Series Code 0421: upper left convection relay shorted 0630Wolf M Series Oven Code 0630: Auxiliary DLB Shorted 1B21Wolf M Series Code 1B21: Cooling fan triac shorted (1B21) 3521Wolf M Series Code 3521: Upper door open or unlocked in clean 1C21Wolf M Series Code 1C21: Both upper bake element DLbs open

CHECKSUMCHECKSUM questions

When does CHECKSUM appear?

The control performs the self-check at power-up and whenever the oven OFF key is pressed. A failure at either of those moments brings up the message on the display.

Is my oven too old to fix?

Not necessarily. We check supply and the controller first and tell you plainly and honestly whether repair is sensible before you pay for any parts.

Will a reset help?

It may clear a one-time glitch after a power interruption at the oven. If CHECKSUM keeps returning, the control's stored data or the board is the likely cause.