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#466452 - 06/26/08 11:33 AM Kenmore stove ECU faults
gone2far Offline
newbie

Registered: 10/02/03
Posts: 16
Hello,

RE: Sears Kenmore 790 46813991 Slide in range (dual fuel).

This rather nice looking Stainless Steel Kenmore “Elite” has an Achilles heel in its ECU control touch pad or has something else related that affects the ECU’s longevity. About a year ago, had the first “F1” fault indicator on the ECU. Not having much information in the service packet attached to the rear panel and no clue what F1 meant at the time. My chronology to date:

Simple application of CRC electronic contact cleaner got it working – back to normal - no F1.

Three months later back to F1. More CRC and back working again. Lasted three weeks this time.

This time I did some better research on what the F1 indication actually means. I read the forum here as well as some other appliance sites. At least I learned I my unit is a Frigidaire (now Electrolux). All comments indicate F1 means a bad ECU so at my wife’s constant urging – I ordered the part.

$300 later I installed the fresh Electronic Control Unit module (ECU) and was back in business. (Replaced the safety thermostat while I was at it).

Not so fast. F1 fault after 3 months (on the new unit).

This time I zeroed in to the Mylar ribbon connector between the keypad and the control circuit – they are built like a sandwich with the ribbon connecting the two boards together. I pulled loose the ribbon and mechanically cleaned both the bare ribbon and the connector receptacle. Worked again!

Two weeks later – another F1 fault. Here I stand today – no stove. (At least the gas top works good).

Now you see my dilemma – at $300 a pop I cannot simply replace ECU’s like fuses. If so, this expensive and out of warranty stove goes to the curb. Before I attempt another ribbon cleaning there is one thing I noticed – there is a small cooling fan at the rear of the cooktop that far as I know has never worked. My thoughts are hear and fumes from cooking are part of the problem. Not sure where to go from here.

Questions:

1) I need advice how to test for a bad fan – the impeller spins freely I have an ohm meter and wondered what to check.

2) I can’t tell from the schematic what the operating voltage of the fan is....220V?

3) Any other ideas I should be looking at?

Look forward to some help on this dilema....

PS Have a schematic but not sure how to attach to this post

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#466453 - 06/26/08 01:43 PM Re: Kenmore stove ECU faults [Re: gone2far]
jeff1 Offline
Carpal Tunnel

Registered: 09/24/03
Posts: 11747
Loc: Ont Canada
Hi,

Quote:

790 46813991




Canadian or American?
Most if not all Canadian Sears models are not online. Frigidaire had no useful info on that model#.

F1 - often a clock/control, key panal or odd time a bad oven temp sensor issue.
http://www.applianceaid.com/fault_codes.html#f1test

Quote:

1) I need advice how to test for a bad fan – the impeller spins freely I have an ohm meter and wondered what to check.

2) I can’t tell from the schematic what the operating voltage of the fan is....220V?




According to the wire diagram, one side goes to a neutral = 120 volts. Often ( not always ) this does not come on right away until the oven has been on a while.

jeff.

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#466454 - 06/26/08 02:23 PM Re: Kenmore stove ECU faults [Re: jeff1]
gone2far Offline
newbie

Registered: 10/02/03
Posts: 16

Hi and thanks for a reply:

In response to you comments

1) This is an American sears unit

2) You appeas to be correct about the fan, wiring shows connected to L2 leg - through a door switch (?) then to neutral. When I test after my makeshift repairs i may have had the door open for front panel access. When the oven did work, I never felt or heard air coming out the small vent opening at the rear of cooktop. Fan is not wired into the ECU directly that I can see just thru L2/N as above - so dont know if the fan is thermally controlled.

3) The parts list show two thermal switches. I replaced one , the "safety thermostat", I replaced it thinking it was a permissive for somthing. The other "Switch thermo cutout" - I didnt.

4) Your link: Yes, I already have that one. I used the test format as described - actually I had done somthing similar previously - and after reading that page came to the decision to replace the control module. Well thats what they recommended and the second lasted a while...

5) Like I said, seems to be the heat What do you think?

6) I had used Frigidare PLCS389DC as a guess while trying to crossreference from thir catalog it sooked like my Sears. No responce when I wrote to Frididare. You have to laugh takling to Sears "You got a what code????"

Thanks for your help...

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#466455 - 06/26/08 09:55 PM Re: Kenmore stove ECU faults [Re: gone2far]
jeff1 Offline
Carpal Tunnel

Registered: 09/24/03
Posts: 11747
Loc: Ont Canada
Quote:

Fan is not wired into the ECU directly that I can see just thru L2/N as above - so dont know if the fan is thermally controlled.




*Should* some how be controlled....either on all the time when the oven is on or thermostatically controlled. Our Frigidaire range has a cooling fan and it will run a while after the oven is shut off = thermostatically controlled somehow.

Quote:

Like I said, seems to be the heat What do you think?




If the cooling fan is ok, both the control and key panal can have issues if overheated. If the cooling fan is not functioning, definetly start there.

Quote:

No responce when I wrote to Frididare




Here?... http://www.frigidaire.com/contact_us_other.asp

jeff.

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#466456 - 06/27/08 05:37 AM Re: Kenmore stove ECU faults [Re: gone2far]
mommapup. Offline
Carpal Tunnel

Registered: 12/19/07
Posts: 16855
Loc: SW Michigan
Oh my, visions of the same nightmare.
Mine is a GE wall unit that started a F7 fault and incessant beeping. Long story short, after doing everything you did and deciding I wasn't gonna pay $180 to fix a $300 oven, I ended up "crimping" the end of the ribbon cable a bit with my fingernail. I think the heat affects the socket of the ribbon cable and the fit is loose. Been about a year since my "crimp/kink" fix.

Just where do they get off charging so dang much for parts? Doggone disposable society.
_________________________
Poverty shouldn't be so comfortable you don't want to work.

“Ideas are more powerful than guns. We would not let our
enemies have guns, why should we let them have ideas?”
--Joseph Stalin

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#466457 - 06/27/08 06:51 AM Re: Kenmore stove ECU faults [Re: mommapup.]
gone2far Offline
newbie

Registered: 10/02/03
Posts: 16

Interesting to see that sombody else had a similar experience.

This weekend I will try your crimp / kink method. How exactly did you do this?

I will also try to verify the fan as good/ not good. Somthing tells me that my fan is the source of all of this...

Frigidare already responded "The cooling fan should run in any cycles" (Huh? French guy from Electrolux)
That didn't help me much - I will write back.

Will keep you posted as I suspect many others have had this happen...

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#466458 - 06/27/08 07:59 AM Re: Kenmore stove ECU faults [Re: gone2far]
mommapup. Offline
Carpal Tunnel

Registered: 12/19/07
Posts: 16855
Loc: SW Michigan
I don't know about that fan, mine doesn't have one, but I do believe the problem is heat related. We all know plastic degrades and can shrink. I figure that's what happened to the socket.

I'm not too sure most folks would deal with it MY way, but just get new or pay the big bucks for the part. Not me, oh no. I can't count the times I removed the 8 screws to get at the guts. Cleaning always worked for a short time. The kinking was a last ditch effort before tossing the dang thing in the trash.

All I did was use my thumbnail to pinch the end of the ribbon enough to get a small kink. Both sides, as there are contacts on both. It's kinda like manipulating the prongs on an electric plug to stay in a socket. So far it has worked very well. Hope this helps.
_________________________
Poverty shouldn't be so comfortable you don't want to work.

“Ideas are more powerful than guns. We would not let our
enemies have guns, why should we let them have ideas?”
--Joseph Stalin

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#466459 - 06/28/08 11:33 PM Re: Kenmore stove ECU faults [Re: gone2far]
didy Offline
member

Registered: 02/19/05
Posts: 109

DISPLAYED FAULT CONDITIONS


IMPORTANT NOTE: Not all EOC’s will display every fault code listed. Some of the F-codes are found
only on older products. For example: F3 on current models can be an open or shorted probe and
they will not display an F4, but on some older models F3 indicates an open probe and F4 indicates a
shorted probe.

F1
Control Failure


Shorted keypad. Internal checksum may have corrupted control relay shorted or bad probe.
Check probe and probe wiring and replace if bad. Power off for 30 seconds. If fault returns replace
control

F2
Oven temperature above specifications:


The oven temp has risen above 665 degrees F and the oven door is not locked or : the oven temp
has risen above 965 degrees F with the door locked.
TEST: Door latch switch or switches; oven sensor (RTD); Electronic oven control (EOC)

F3
The RTD is open/shorted


Check for open wiring connections between EOC and RTD. Check resistance of RTD using resistance table. If resistance test is correct and wiring is good to board replace EOC.

F4

Shorted oven sensor (RTD)
Check for shorted wiring between EOC and RTD. Check resistance of RTD using resistance table. If
resistance test is correct and wiring is good replace EOC.

F5
The watchdog circuit is active when it should be disabled.


The microprocessor checked for operation of EOC relay after selection of Bake, Broil, or Clean operation and relay failed test. Check for shorted keypad or pushbuttons binding in glass and stuck. If not
replace EOC.

F6
No 60 Hz base


Time base is required for time controlled cycling. Replace EOC.

F7
Lock motor relay watchdog circuit active when it should be disabled.


The microprocessor checked for operation of the EOC lock relay after selection, and the relay failed
the test. Replace EOC

F8/F9
Lock motor switches improperly positioned. The microprocessor has found the lock motor switches to be out of sequence or shorted. Test switches and if found to be good and in proper sequence
then replace EOC.



On freestanding gas and electric ranges manufactured beginning with the serial number date code
VF426 many of the EOC’s will have expanded three digit fault codes. These codes may also appear
in new replacement EOC’s for ranges built prior to this date. Below is a list of possible fault codes
that might appear in the EOC display window. The original two digit fault codes appear in the shaded
boxes followed by the replacement three digit codes.

EOC Failure / Fault Codes

For each Fault code there is a listing of the likely failure condition or cause, as well as suggested
corrective actions to be taken. Not all fault codes will appear in every model but the fault codes are
universal and have the same meaning regardless of the model that is being serviced


Note: Fault codes are not a foolproof system. Never assume that a part has failed based on a displayed
fault code. An example would be if the EOC is displaying F30 (open sensor), the failure could be caused
by a loose connection or faulty wire harness between the EOC and sensor or the sensor could simply
be unplugged.

FAULT CODE LIKELY FAILURE CONDITION/CAUSE SUGGESTED CORRECTIVE ACTION
F10
F11
F12
F13
F14
F1
Runaway Temperature.
Shorted Keypad.
Bad Micro Identification.
Bad EEPROM Identifi cation/Checksum error.
Display tail missing/not connected
1. (F10 only) Check RTD Sensor Probe & replace if necessary.
If oven is overheating, disconnect power. If oven continues to
overheat when the power is reapplied, replace EOC. Severe
overheating may require the entire oven to be replaced should
damage be extensive.
2. (F11, 12 & 13) Disconnect power, wait 30 seconds and reapply
power. If fault returns upon power-up, replace EOC.
3. (F14 only) Re-seat the P12 ribbon connector tail. If fault returns replace EOC (first action); Touch Panel (second action)
F20
F26
Communication failure between EOC and ESEC
system.
Communication failure with mini oven control.
1. Test harness/connections P4 (EOC) & P11 (Surface element
control board).
2. If harness checks O.K. failure can be caused by faulty UIB,
surface element control board, or EOC.
Check harness and connectors from the EOC to mini oven
control board. Check for 15vdc to mini oven control (red & gray
wires). If harness and voltage are good replace mini oven control. If fault returns replace EOC.
F30
F31
F3
Open probe connection.
Shorted Probe connection
1. (F30 or F31) Check resistance at room temperature & compare to RTD Sensor resistance chart. If resistance does not
match the RTD chart replace RTD Sensor Probe. Check Sensor
wiring harness between EOC & Sensor Probe connector.
2. (F30 or F31) Check resistance at room temperature, if less
than 500 ohms, replace RTD Sensor Probe. Check for shorted
Sensor Probe harness between EOC & Probe connector.
F40
F41
Cooktop Lockout error. 1. (F40 or F41) Check the wiring.
2. (F40 or F41) Replace the Cooktop Lockout Control Board.
3. (F40 or F41) Replace EOC.
F90
F91
F92
F93
F94
F9
Maximum oven door unlock time exceeded.
Maximum oven door unlock attempts exceeded.
Maximum oven door open time exceeded.
Maximum oven door lock time exceeded.
Maximum oven door lock attempts exceeded.
1. (F90, 91, 92, 93 & 94) Check the wiring between EOC & Lock
Motor Micro Switch.
2. (F90, 91, 92, 93 & 94) Replace the Motor Door Latch assembly if necessary.
3. (F90, 91, 92, 93 & 94) Check for binding of the Latch Cam,
Lock Motor Rod & Lock Motor Cam.
4. (F90, 91, 92, 93 & 94) Check to see if Lock Motor Coil is open.
If open, replace Lock Motor Assembly.
5. (F90, 91, 92, 93 & 94) Lock Motor continuously runs - if Micro
Switch is open, replace Lock Motor Assembly.
6. (F92, 93 & 94) Check oven door Light Switch - if open, replace
Switch.
7. If all situations above do not solve problem, replace EOC.



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#466460 - 06/30/08 11:53 AM Re: Kenmore stove ECU faults [Re: mommapup.]
gone2far Offline
newbie

Registered: 10/02/03
Posts: 16

To follow up on the saga - I spent the majority of Saturday once again sliding out the slide-out range and pulondg loose the ECU for some monor surgery. Using Bozodogs' advice, I set about to provide the "perfect" kink in the interconnecting ribbon. On my stove, and probable many others, there is a sandwitch of two circuit boards - one having the bubble membrane keypad and display the other the main processor / power control IC's that basically power the oven. The assembley is aproximately 14" x 5" rectangle, 3/4' thick with a 10-12 element ribbon connecting the two in the shape of the letter "U" - with the ribbon at the bottom of the U looking from the side. The ribbon makes a contact-fit into a female socket on the power board.

I am thinking that this ribbon / socket is THE problem. It took four tries to get the crimp just right - so it have positive contact with each of the pins or "jaws" on the socket. My mylar ribbon was fairly stiff and hard to bend - so after three aborted F1 signals - I bent it pretty hard and it worked. It worked all day Saturday and Sunday - then went into fault (F1) Monday morning. Somthing tells me the Mylar has "memory" and straightened back to origional shape.

Once again, $1,800 stove - 2004 vintage, already the second ECU (I replaced the first), and I think I have a 25 cent connector interrupting streams of data between the boards.

Replace the ECU again? Not on your life at $327 including tax and shipping. Any final thoughts before the recycler gets my little beauty? Nice design defect Sears - Frigidare.

Would anyone consider soldering some small wires in place of the ribbon for a permanent solution? That's a $2,000 dollar question.

I typed at legnth about how to test my fan (thought failures were heat related under normal operation). Fan works fine. It only works during cleaning cycle and it is conrolled ONLY by a door switch. A motor turns a safety lock on the door which trips the fan. Shoot, pretty cool although I never got the oven dirty enough to use this feature. At least I know the fan doesnt work during normal operations.

I write all of this as I KNOW sombody will have this problem too - sooner or later. OTHER than getting out my Weller solder gun or finding somebody with smaller fingers than me who has a microscope to do the ribbon work - Looks like I am out of luck. I will think twice about a digital display/keypad in the future!

You guys rock in this forum.....

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#466461 - 06/30/08 01:23 PM Re: Kenmore stove ECU faults [Re: gone2far]
mommapup. Offline
Carpal Tunnel

Registered: 12/19/07
Posts: 16855
Loc: SW Michigan
Sorry the fix didn't work for you. I had to kink mine a few times to get it to stay. Although it's only been a year since the fix, I agree with you. Why use/put plastics in a high temp area? I know it's my socket too, but at least I can reach mine by taking the front display panel off.
_________________________
Poverty shouldn't be so comfortable you don't want to work.

“Ideas are more powerful than guns. We would not let our
enemies have guns, why should we let them have ideas?”
--Joseph Stalin

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#466462 - 06/30/08 03:11 PM Re: Kenmore stove ECU faults [Re: gone2far]
jeff1 Offline
Carpal Tunnel

Registered: 09/24/03
Posts: 11747
Loc: Ont Canada
Quote:

Fan works fine. It only works during cleaning cycle and it is conrolled ONLY by a door switch. A motor turns a safety lock on the door which trips the fan. Shoot, pretty cool although I never got the oven dirty enough to use this feature. At least I know the fan doesnt work during normal operations.




Interesting!
That could help others

jeff.

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#466463 - 08/30/08 09:40 AM Solution to Kenmore F7 Error [Re: gone2far]
arnieg Offline
first timer

Registered: 08/30/08
Posts: 1
A permanent fix for the GE/Kenmore F7 error problem was developed by Charlie Popeck, a professional engineer. It involves inserting a piece of paper between two ribbon cables to eliminate the possibility of short circuit between the two cables. The 30 minute procedure is described (including photos) at the web site

http://www.fixya.com/howto/h155060-dreaded_f7_error

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#466464 - 04/23/09 11:55 AM Re: Kenmore stove ECU faults [Re: gone2far]
Gautami Offline
newbie

Registered: 04/23/09
Posts: 2
I've had the F1 problem several times now on a Kenmore Elite Duel Fuel (468130). The first time we called a repairman and he took out the ECU and peeled off the membrane keypad. He worked the flexible keypad around to free up any stuck contacts. Then he put it back together and it was fine - for awhile. Then it came back. I've had to do this a couple of times since.

I've also been able fix it a couple of times by taking a paper towel and briskly rubbing the buttons - trying to unstick them without taking anything apart.

Yesterday, the F1 came back again and the rubbing trick didn't work. So I took it apart again. After roughhousing the membrane keypad, I carefully positioned the control unit and turned the power on and tested the buttons. Everything worked fine. So I turned the power back off and put everything back together. When I turned the power on again, the LOCK indicator was on (as were the oven lights). The clock, kitchen timer, oven cook time, stop time, clear and the child safety lock buttons all work, but none of the other buttons that actually do stuff work. Well, the buttons work, but there are three rapid beeps when you press any of them.

What could I have done wrong during the reassembly to cause this? According to the manual, the LOCK indicator should be lit after cleaning until the oven is cool enough to open. Leaving the power off overnight did not work.

Thanks

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#466465 - 04/23/09 01:18 PM Re: Kenmore stove ECU faults [Re: Gautami]
jeff1 Offline
Carpal Tunnel

Registered: 09/24/03
Posts: 11747
Loc: Ont Canada
Hi,

Quote:

What could I have done wrong during the reassembly to cause this?




Damaged the key panal, damaged the clock, damaged/bent/piched a wire....would have to be investigated.

Quote:

Kenmore Elite Duel Fuel (468130).




Kenmore model#'s are more like 123.45678910



http://www.applianceaid.com/fault_codes.html#f1test

JMO!

jeff.

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#466466 - 04/23/09 02:00 PM Re: Kenmore stove ECU faults [Re: jeff1]
Gautami Offline
newbie

Registered: 04/23/09
Posts: 2
Just the number above is on my label, although if I google 790.468130 I do get a hit at an appliance parts site (slide in duel fuel range). The parts look right, but the control panel or other identifying parts are not pictured.

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#466467 - 04/23/09 05:14 PM Re: Kenmore stove ECU faults [Re: Gautami]
jeff1 Offline
Carpal Tunnel

Registered: 09/24/03
Posts: 11747
Loc: Ont Canada
Quote:

790.468130




790.######## is a WCI/Frigidaire built kenmore.
If this is a Canadian model, most/many Canadian models are not online.

jeff.

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