Service Guide
For Service Technician Use Only
DIAGNOSTICS & TROUBLESHOOTING
2-12
n
Whirlpool
®
Smart Wall Ovens
Code Description Explanation and Recommended Procedure
F4 Inputs
E4
Microwave Oven
Humidity Sensor
Error
NOTE: Before starng any test, cycle power to the oven (power o, wait 10 seconds, and then
power on). Aer powering on, be sure that a load, such as a microwave-safe cup of water, is
present in the microwave oven cavity, and start a microwave cooking funcon that uses the
humidity sensor, such as a Steam cycle. Wait 1 minute, then verify that the failure happens
again.
1. Unplug the oven or disconnect power.
2. Check that the P23 connecon of the Microwave ACU is rmly connected. If it is, go to Step
3. If it is not, reconnect and go to Step 5.
3. Disconnect connector P23 from Microwave ACU and measure the resistance of the sensor:
Between pins 3 and 1, it should be approximately 2800Ω at 77°F ± 10°F (25°C ± 10°C).
Between pins 3 and 2, it should be approximately 2800Ω at 77°F ± 10°F (25°C ± 10°C).
4. Check sensor for short to ground. If checks on sensor are not correct, replace the sensor. If
sensor checks are correct, replace the Microwave ACU.
5. Reassemble all parts and panels before operang.
6. Plug in the oven or reconnect power.
7. Verify operaon is normal. Enter the Diagnoscs Menu, select “Error Diagnoscs”, and clear
the history.
F4E8 Inverter Over
Temperature
NOTE: Before starng any test, cycle power to the oven (power o, wait 10 seconds, then power
on). Aer powering on, be sure that a load, such as a microwave safe cup of water, is present in
the microwave oven cavity, and start a microwave cooking funcon. Wait
1 minute, then verify that the failure happens again.
1. Unplug the oven or disconnect power.
2. Check the following:
a. Cooling fan connecon for any loose connectors.
b. Oven installaon and make sure there is no air blockage at the boom vent.
3. Reassemble all parts and panels before operang.
4. Plug in microwave oven or reconnect power.
5. To check if the cooling fan is stalled, be sure that a load, such as a microwave-safe cup of
water, is present in the microwave oven cavity, and start a cooking funcon in the microwave
oven. Make sure the fan is running. If it is not, unplug the oven or disconnect power, replace
the fan and go to Step 8. If it is, go to Step 6.
6. Unplug microwave oven or disconnect power.
7. Replace the inverter board.
8. Reassemble all parts and panels before operang.
9. Plug in the oven or reconnect power.
10. Verify operaon is normal. Enter the Diagnoscs Menu, select “Error Diagnoscs”, and clear
the history.
ACU
Humidity
Microwave
Sensor
1600
P23