XSeries-forum

I have seen this fault code before on a 5 series though (same engine as yours) he was getting poor starting and erratic tick over
The diagnostics pointed to P1632
Defective or weak vehicle battery
Damaged alternator or generator
Loose or corroded battery terminals
Faulty voltage regulator module
Broken cable connections in the charging system
Faulty earth connections
Problems with the battery management system (BMS)

The issue we traced was poor earth connections replacing the engine earth straps and a new battery fixed it

Thanks for your help!
Your on point!
I installed a new battery couple days ago...
Ground straps I added a couple additional several years ago. The ground strap around the motor mount is a negative battery cable for a lawn mower! This has worked in the past!
The latest culprit is the throttle body and the three nipple connection in back of the intake.
I've capped off all three nipple.
I've got an aftermarket tb at the garage we'll see if that erases the surging idle.
Thanks again...