In brief
Jenn-Air documents 4d42 as cooling fan speed too high. The control watches how fast the fan that cools its electronics is turning, and a reading above the expected range means either the fan really is spinning too fast or the speed signal is wrong. Listen to the fan before anything else: a change in its sound settles which.
Error codes
Reference| Code | Meaning |
|---|---|
| 4d42 | Cooling fan speed too high. |
What you observe
- The fan sounds the same as always — An unchanged sound points at the speed signal rather than the fan itself.
- The fan keeps running after the oven is off — Some run-on while the oven cools is normal; a fan that never stops is worth noting.
- NEAR MISS: a noisy convection fan — The convection fan inside the cavity is a different fan from the cooling fan behind the panels.
Likely causes, ranked
- The fan speed signal — Ranked first when 4d42 appears while the fan sounds the way it always has: if nothing audible has changed, the speed reading is a likelier culprit than the fan.
- A connector loosened by heat — Connections near the fan see heat and vibration and can give an unstable speed reading.
- The circuit that drives the fan — If the part that sets fan speed is stuck at full output, the fan runs at top speed all the time.
Diagnostic order, cheapest and safest first
- Listen to the fan — With the oven heating, listen near the vents for a rattle, a scrape or a higher pitch than usual.
- Reset once, cold — With the oven cool, switch it off at the breaker for a few minutes and back on.
- Note when it appears — At start-up, during a long cook or while cooling down: the timing tells a technician where to look.
Clearing the code and safe checks
- Reset at the breaker — With the oven cool, breaker off for a few minutes, then on.
About 5 min
- Run a short bake and listen — Set an ordinary bake and listen near the vents through the first minutes of heating.
About 10 min
- Record what you hear and when — Write down the code, the sound and the point in the cook when it appeared.
Tools: notebook or phoneAbout 3 min
- Stop before any panel comes off — Everything past this point needs live measurements or a panel removed; that is the line between an owner check and a service call.
Safety before any check
Safety
Unplug the appliance or switch off its breaker before removing any panel. A capacitor can hold a charge after the power is off. A cooling fan can start without warning whenever the oven is powered, and the area around it gets hot; never push anything into the vents, and keep the oven off at the breaker before checking near them.
Reset or service call?
Call for service if 4d42 returns after a reset, or straight away if the fan rattles, scrapes or never stops. Testing the fan speed and its signal needs panels off with the circuit live.
Nearby codes on the same oven line
Generalized information
Scope: the documented meaning of 4d42 for Jenn-Air ovens whose code list carries 4d42 as a cooling fan speed fault. Out of scope: convection fan faults, fan speed too low codes, and models that read 4d42 differently; so is model-level detail such as connector positions and part numbers. A model-specific page, where one exists, is the more precise source.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
