Hey everyone! I'm really struggling here with my car, and was hoping that your infinite knowledge could help me.

I currently own a 2003 Infiniti M45 that is suffering from IMMU failure. The codes that were brought up were the same ones related to the BCM, which upon close inspection seems to have a capacitor burnt up.

I replaced the BCM and plugged it in, but I cannot access it through Consult II, the Nissan program you can get on your PC. The ECM connects no problem, but to actually reprogram the keys I need the two systems to talk to one another.

The other issue is I don't have the pin code. I'm aware of the universal pin code being "5523" but they allegedly switched to needing a decoder in the 03 G35, so I'm not sure where this one fits. It's still a white casing with no label, but I'm not sure if that definitively means that it's 5523.

I'd be happy to take it to a local shop or locksmith (Richmond VA locale) but from the great many places I've called they either don't have a clue what to do about it, or they're Infiniti themselves saying they don't take in older cars unless I give them a $500 security deposit, which feels slimy.

Let me know what you guys think though, I really would appreciate the help. Whether it's a different program that'll work, a new method, or whatever. Thanks much!

The BCM isn't involved in key reading or registration on an '03, it only handles the alarm system and doesn't participate in starting the car. The IMMU, ESCL (steering lock), and ECM are the only controllers involved. See BL-157 here for how it works and BL-161 for the wiring diagram:
https://www.nicoclub.com/service-manual ... 3%2Fbl.pdf

To my knowledge, all the N/I products with standalone IMMU's use the 5523 code. You're not actually talking to the IMMU when you initialize for key registration with Consult. You're only talking to the ECM, which then communicates with the IMMU via a bit-bang comm line. You have two cabin fuse blocks in your M, one in the lefthand kick panel and the other in the righthand. The fuse for the IMMU is in the righthand one, make sure it's good.

Search/Google for this TSB: ITB02-068a. DM or post a pic of the label on the IMMU and I can assist with the PIN.

VStar650CL wrote: ↑

Mon Oct 23, 2023 3:05 pm

To my knowledge, all the N/I products with standalone IMMU's use the 5523 code.

Only for the USA market.

Google search came up dry, but I found the bulletin in ASIST. Here's a link for anyone who might need it:
https://drive.google.com/file/d/1bjyTW_ ... sp=sharing

That's pretty unique, but I guess the first couple years of any new system will have some unique attributes. I may never see one of these, but great info, @Costee, tyvm.