2003 Deville

The fuel volume regulator control code is a mystery, as it has no such thing on the vehicle. The banks 1-2 lean codes are often caused by an unmetered air leak. On this vehicle, one of the most common locations is the plenum boot between the intake manifold, and the throttle housing. The rubber cracks causing a vacuum leak. The p0741 and p1860 are common also, the preferred repair is to have the transmission removed and reseal the TCC hydraulic circuit, replacing the torque converter, and the TCC solenoid. There is no one specific cause for this, and being as that it is inside of the transmission, and the difficulty of getting the transmission out, you only want to do the job once.

The boot should be a seperate part from and intake kit. It may not be available aftermarket, if that is where you are getting your part. To remove it, you need to remove the fuel rail to access all of the intake bolts, and remove the three bolts that come from the throttle body side. It is the part that is clamped at the intake, and bolted at the throttle housing with the same bolts that mount the throttle body.