that last rigid pipe with the hook in it is your front differential breather. Just leave it alone, nothing connects to it. Yes, when you first turn the key on, the "check engine" light should come on. Very common for someone to take cluster apart and disable. If you have INPA, you need to clear ALL faults and start over. There could be years of stored codes in there, you need to start with a clean slate. Your hacked wiring could be stopping you from accessing modules. HENCE our advice to fix any wiring that you know of asap.

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Dave S.
Northeast
2003 4.6is
2005 E53 4.4
2003 E39 Msport(a REAL ONE!)
1959 Fiat 600