Model #KEMC207KBL04, both ovens on this built in unit were functioning perfectly well for the customer until she went to self clean each of them. The top oven locked and cleaned just fine, but when the clean cycle was started for the lower oven, the oven locked the door, then displayed an F5 E1 error message. This was bad enough, but it didn't just stop the lower oven from working. When the start button was pressed for the upper oven, the display said 'Oven to Hot' and would not heat. With both ovens out of commission, the customer was desperate for a solution.
During the typical self cleaning cycle of an oven, the interior temperature can reach well above 700 degrees, essentially turning the oven into an incinerator. To protect someone from opening the door during this cycle, all self clean ovens are equipped with a locking mechanism that will remain locked until the oven has returned to a low enough temperature for the door to be safely opened. These locks can either have a mechanical thermostat to operate the lock, or in the case of electronic controls, the internal oven sensor will be used, along with a motorised locking mechanism.
The latch mechanism themselves will have a position switch that the electronic control uses to determine the position of the latch. This along with the door switch is used to ensure the door is closed before the latch motor is actuated to lock the door. If either switch is not in its expected position once the lock is engaged, the clean cycle will not start, and in many cases, an error message will be displayed.
On this double oven, each door has it's own latch mechanism that consists of a motor, a position switch, and the door switch used to activate the cavity lights. Because the error indicated a latch failure (and the bottom door was locked), I started by cycling the power to the unit. Each time the power is removed and then applied to these ovens, both latches will lock then unlock the doors to ensure they are in the home open position. By doing so, I was able to get the bottom oven door opened allowing me access to the latch assembly. With the latch removed, I tried to begin a clean cycle so I could watch the motor operate and found it would start to turn, but never would rotate enough to lock the door. Since the position switch was not actuated at the end of the motor operation, the F5 E1 error was again displayed.
Simple enough problem to fix by replacing the defective latch with a new latch assembly. These latches can fail over time as they are subjected to the heat from the self clean cycle numerous times. Just like this one did. But once the latch was replaced, both ovens were again working properly for the customer.
Just a Note: there was an interesting issue with this call because both ovens failed to function due to one component failing, which is not was I would normally expect. The 'Oven to Hot' error doesn't make sense to me because the electronic control was reading the position of the lower latch position switch and determining the oven was still to hot as if it was at the end of a self clean cycle. I would have expected the electronics to at least sample the cavity temperatures from the oven sensors before displaying the error, but it looks like the way this unit failed caught the electronics in a place where they picked a safe mode. Cycling the power cleared the error, but as I said, it is not what I would have expected.