99 Mustang Gt Instrument cluster and pcm

Hellmo

New Member
Oct 29, 2020
1
0
1
28
Florida
What's the best way to clear codes in the instrument cluster? Trying to figure out a pats issue. Found out the pcm in the car was not communicating with obd2 so I swapped a donor pcm and instrument cluster that came with the car in. Was told the cluster and pcm were out of the same car by seller. No dtc's with obd2 reader (cheap one). When using cluster diagnostic mode, the code for security values in cluster and pcm don't match was shown. I want to try and reset the codes so I can make sure its not from a previous swap the seller may have tried. Donor PCM connects to obd2 reader and also mileage shows up. I know they can be married at a dealer but I don't have one close, nor a way to get car there (money). Are the codes stored in the cluster or the pcm? Sorry for the rambling post and million questions. Thanks for anyone's help in advance.
 
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wmburns

SN Certified Technician
Aug 14, 2009
5,849
507
204
Houston Texas
Just wondering. How do you know that the cluster and PCM are able to "talk" to each other?

Have you CONFIRMED that the PCM is actually getting power? Powers and grounds at the PCM? You are aware that IF the PCM is not getting power this will appear to be a PATS issue.

Does the cluster display all dashes (-------) or mileage?

IMO your problem is much more basic than clearing codes.
 

SMOKEDYA

15 Year Member
Jul 13, 2003
3,627
8
79
Tucson AZ
Having sorta this same issue. My 02 gt cluster reads all dashes cranks wont start no fans come on no fuel pump prime, theft light flashes rapidly then goes out briefly followed by what i have read is a code 16. Neighbor plugged in his scanner to my OBD port and ECM is not communicating with OBD port. Previous owner replaced CCRM,key antenna for key,fuel pump driver, fuel pump
 

wmburns

SN Certified Technician
Aug 14, 2009
5,849
507
204
Houston Texas
Here's some information that IF followed would get you well started on the road to finding a solution.

1996+ Crank with no start check list
 

SMOKEDYA

15 Year Member
Jul 13, 2003
3,627
8
79
Tucson AZ
Here's some information that IF followed would get you well started on the road to finding a solution.

1996+ Crank with no start check list
Thanks for the response, I actually googled this issue and ran threw the tests you listed.. said :leghump: it! Part out!