2002 S600 (220 178, with M137.970)...

What functions does the Steering Column Module (025 545 44 32) oversee in this vehicle?

All inputs from combi-switch, steering wheel buttons, etc. are sent to CAN via the SCM. Driver's side airbag does NOT go thru SCM.

Can a faulty SCM module affect engine performance?

At present, the vehicle has a P2031 fault code (stored and current) in the ME-SFI 2.7 Motor Electronics system indicating "no or incorrect CAN message from the steering column module (SCM; control unit N80)."
Yet, all of the steering wheel & column pushbuttons and switches are functional.

Trying to solve a driveability issue that feels similar to a failing mass air flow sensor... reduced performance, esp. when accelerating on an incline... but no adaptation changes are noted in the real time data.

An SCM fault (C1035) has also appeared in the ESP system and, of course, in the SCM system (B1000-009), indicating the control unit is faulty.

Can restoring engine performance be as simple as just replacing the N80 control unit? In addition to its steering column switch and buttons functions, does the N80 also act as a CAN gateway for the ME-SFI?

No, the SCM isn't a gateway to ME-SFI. Depending on the year of the vehicle, either the EIS or Central Gateway is responsible for that function.

If the steering wheel buttons and combi-switch functions are good the SCM is working fine.


For your driveability issues, stick with the basics first. Your description makes me think you may have a fuel delivery problem.