Thermador oven won't fire up

Oven/Range/Cooktop Repair
1

I’ve got a problem with the oven on a Thermador range.
Just in time for Thanksgiving.
First I can’t find the range on the Thermador web site.
The label says:
Thermador
Customer Service 1-800-735-4328
Model P366CS/03
ID 860500001
Serial 39605008371

Oven appears to turn on but then turns off with lights flashing a code:
Preheating – 4 blinks
Heating – 3 blinks

I can see the igniter glowing red hot.
As the igniter is glowing, the voltage on the terminals to the gas safety valve rise up to 3VAC. But then everything clicks off and the error code blinks as described earlier.

Is it the safety valve or is it the control board?
Or both?
The control board relays seem to be clicking strongly.

Thermador Range/Stove/Oven Safety Valve - Bosch OEM Part #00605061
Is there a way to check the safety valve on a bench?
It says operating voltage 3.3VAC.

Any suggestions appreciated.

This range is a bear to work on.
I’ve never seen so many screws.
And the stove top burner heads are seized up.
Does anyone know of a way to get the burner heads removed without too much destruction?
I am prepared to buy replacement parts for 4 out of 6 of the burner heads.
What a mess!
Thank you in advance for taking the time to read this.
Best wishes for the holidays.

2

Here’s an update.
The oven worked for one day. Thanksgiving Day.
The turkey got cooked.
But the next day, error code 43 was back again.

It was neither the gas safety valve nor the control board.
After researching the web, I found that error code 43 is “No Cooling Fans.”
I also learned that there’s a small interlock switch just below the cook top. It’s described as a sail switch.
The interlock switch was caked with grease.
I cleaned the grease off and the oven worked.
Now the next day, error code 43 is back again.
I checked the interlock switch. The heat from the cooking must have melted another load of grease into the switch.
So I bypassed the switch until I can get a replacement.
The oven ignites okay, starts to get warm, then clicks off and blinks error code 43.
Please, can someone help?

3

I had the same problem. Thermador pg304 LP. Two fans not made any more. I tried to clean them in place as well as the sail switches. It didnt work. I removed them (horrible job) and thoroughly cleaned both the fan blades and the switches. You can get a spray electronics cleaner that will clean the switch without ruining it. Relube the fan bearing and reinstall. Mine has worked fine ever since