4x4 MIL on but no code

[mpieklik]

My wife has a 2006 X5 4.4 with 65k miles on it, the other day she said the 4x4 malfunction indicator light came on. After she got it home the MIL was off (vehicle was turned on/off a couple times) put the code reader (Actron CP9575) on it and it said no stored codes...so I thought it was because the X5 was shut off before getting it home.

Second time the 4x4 MIL comes on, code reader is already in the vehicle, have wife plug the Actron in before shutting the vehicle off, still no codes, and does not even show that MIL is on.

Anyone have an idea of why the reader is not pulling the codes...wrong reader, not really throwing a code even though the MIL, etc?

Thanks,
Matt