I have a CEL coming on after driving about 5 miles or so. After doing a KOEO check I can pull code #72 which is in the CM part of the test. The KOER test shows no codes at all. I have done this test 3 different times without any changes in the results. Code 72 in CM and no other codes and no codes at all KOER.
Code 72 from the CM is supposed to be a power interruption but exactly from where to where?
Any help? I'm kind of tired of the CEL coming on. Thanks

 

Ok,so I thought about this on my way to work today and realized that a CM code wouldn't turn on a check engine light. A CM code is a stored code. So whatever is turning on my CEL has to be a real time code. But why doesn't it show up on my KOER test. I probably need to do this test while the CEL is on to try to figure it out. I did the test as soon as I got home when the CEL was on before but I shut the truck off and had to go in the house and get my shorting wire and it probably was off by the time I did the test. I'll try to test it without turning the truck off when the CEL is on today.

 

What year/model/engine truck do you have?

My Ford service manual indicates Code 72 is a KOER code only.

DTC 72 indicates that the MAP sensor output did not change enough during the Dynamic Response Test.

Possible causes:

-- System failed to detect partial WOT.

-- MAP sensor vacuum supply hose improper routing, blockage and/or linkage.

-- Damaged MAP sensor.

l Rerun Engine Running Self-Test. Be sure a complete WOT is performed during the Dynamic Response portion of the test.

 

I forgot to post the truck info. 1994 F250 5.8l 4x4 .
I don't get any DTC when doing the KOER test. I get I think a single flash paused by 2 sec intervals about 5 or 6 times at the end of the test.They don't repeat like DTC codes do so I think I don't have any codes on that test. Trust me I get them when I don't do the test properly. I have had a couple user error codes while perfecting the DIY code reading.I'm doing the counting method with the shorting wire .
I do get the code # 72 doing the KOEO test. That is the only time I get a code and since it repeats at the end of the test I think its a valid code.

 

I forgot to post the truck info. 1994 F250 5.8l 4x4 .
I don't get any DTC when doing the KOER test. I get I think a single flash paused by 2 sec intervals about 5 or 6 times at the end of the test.They don't repeat like DTC codes do so I think I don't have any codes on that test. Trust me I get them when I don't do the test properly. I have had a couple user error codes while perfecting the DIY code reading.I'm doing the counting method with the shorting wire .
I do get the code # 72 doing the KOEO test. That is the only time I get a code and since it repeats at the end of the test I think its a valid code.

 

Ford started the transition to three digit codes in 1991. It would be extremely rare for your 1994 model year truck to display two digit codes. Not impossible, but highly unlikely. This would explain why you think you are getting a Code 72 for KOEO/CM. It's a KOER only Code.

I trust my Ford Truck service manual more than the generic code lists you find online. There can (and is) different code definitions between cars and trucks.

 

The last couple times I have driven the truck,I didn't get a CEL so I thought I would retrieve the codes doing a KOEO test to see what stored codes I had. I got a #72 code again. I did some poking around and found I could move my negative battery post around without much effort. I tightened it up.I'll drive the truck and see what happens.

 

Well today I finally got a chance to drive the truck and I took about 100 mile trip. On the way out after 30 miles or so the check engine light came on and stayed illuminated for the rest of the 100 miles. On the way back,no CEL . This evening after getting home I ran both the KOEO test and the KOER test. the only code I recieved was late in the KOEO test. I'm sure it was from the CM part of the test( after about 8 single flashes spaced apart by about 2 sec and the 2nd to last space was 4 or 5 sec) and it showed a code #72.
Any ideas? I don't have the manual for my year truck but my online search has shown it to be a power interruption or message center control assembly circuit failed.
Member RLA 2005 said my truck was new enough it should show 3 digit codes but that is not what I'm getting and that is verified by the repeat of the code which is only 2 digits 7 flashes of the CEL followed by 2 flashes.
If it makes any difference my truck is GVWR is over 8600#.

 

"I'm sure it was from the CM part of the test( after about 8 single flashes spaced apart by about 2 sec and the 2nd to last space was 4 or 5 sec) and it showed a code #72."

The 8 flashes before your "Code 72" mean something. My Ford Truck Service manual shows Code 72 is a Key On Engine Running (KOER) only code. As I stated before your truck will most likely display 3 digit codes.

The references you may have found for a CM Code 72 is for other Ford models, but I am confident it does not apply to your truck.

 

I should have said that a little differently. After a single CEL flash separated by a sec or so about 7 times then a 4 sec or so pause then a another single flash of the CEL a sec pause then the 7 flashes followed by 2 flashes. Another sec pause then there is one more CEL flash. Then the repeat of the 7 flashes of the CEL followed by 2 flashes.
It sure seems like a 72 code but I'm thinking of buying a code reader. I did a search here and a member said a code reader retrieved a code from the computer he wasn't getting from the shorting method. It might be worth a try. Its either that or just replace the computer with another one. I hate throwing money at it but I didn't have a single issue with the way it ran until a month or so ago when the stator in the distributor went out. After doing what little testing I needed to do to find out the stator was bad maybe I hurt the computer.

 

It may be worth the time and effort (15-20 minutes) to pull out the PCM so you can note the part number and code listed on the label. Then open it up to inspect for signs of leaking capacitors, burn marks or water damage.

If you go that route then please list the numbers from the label on the PCM. Perhaps someone has swapped in one from a car?

For reference: Fuel Injection Technical Library » EEC Program Codes

I also suggest a code reader. Counting flashes does get tedious after awhile. The Equus 3145 is highly recommended. Be aware many readers (this one too) may display the separator flash as a code 10. This is considered normal.

 

I bought this truck 6 years ago from the original owner. He was pretty honest and told me everything what was wrong with the truck( ie trans flutter ).
He never had any other issues with the truck and recorded his maintenance in the owners manual. So I think this is probably the original computer.
Can you point out a link to how to get the computer out in 20 minutes? I've been looking but haven't found one yet. Heck,I've probably spent more than 20 minutes looking for info. Thanks

 

Link:

https://www.ford-trucks.com/forums/1...ble-check.html

Some photos:


courtesy of subford


courtesy of subford

 

Thanks, with the pics and some help from a post in the the Bronco forum here it was easy to get in and out. Have the part # and checked it for damage( water intrusion and burns) looked good.Put back in until I can get another one.
And the best part,it started back up which is good.I have to use my truck to get to work at 3:30am tomorrow.

 

What were the numbers on your PCM?