Check engine light comes on when cooling fans are running.

Whenever the coolant fan is running on my 1993 C4, the check engine light comes on. The light eventually will turn off when the coolant fan is turned off. I scanned it and the codes were 44 & 64 (both codes reflect engine running to lean).
I replaced the oxygen sensor and the MAP sensor, and the light still come on. Could it be the coolant temperature sensor? I don't know. I am running out of options. If anyone has ran into this particular problem?

recently my Escalade had this problem found fuel pump pressure was low 47 instead of 53+ caused lean error

|UPDATED|6/29/2016 9:19:55 AM (AZT)|/UPDATED|

I never had this problem but based on the codes, I would check the fuel pressure as previously stated and check for vacuum leaks.

This ia a follow up on my original post. Thanks for the replies I gotten. The check engine light only comes on when the cooling fans comes on. I flashed the codes again, and they came up the same-codes 44 & 64. And, there were two new codes as well-55 & 63. Code 55 is engine running lean, but code 63 in the Chilton manual says that it can be a faulty ECM or ECM ground circuit. So, with that being said, the problem is the ECM. I already ordered the ECM from Rock Auto. I will keep you guys updated on what the outcome is. Thanks.