3/9/24, 5:20 AM

12 07 21_B58C/D (48V SYSTEM): Belt Slip Fault 21B209

SIB 12 07 21
B58C/D (48V SYSTEM): Belt Slip Fault 21B209

2024-03-04

This Service Information Bulletin (Revision 3) replaces SI B12 07 21 dated November 2023.
What’s New (Specific text highlighted):
Parts List Updated

MODEL
G05 (X5 Sports
Activity Vehicle)
G22 (4 Series Coupe)

G06 (X6 Sports
Activity Coupe)
G30 (5 Series Sedan)

G07 (X7 Sports
Activity Vehicle)
G32 (640i xDrive Gran
Turismo)

G20 (3 Series Sedan)

With the B58C/D and
48V system

SITUATION
Check Control message (CCM) indicates:

(ID 213): Stop, exercising due care. Voltage supply
The Service Engine Soon light is on with the following DME Fault Code:

21B209 - Starter alternator / belt for 48V system (OSA_RIEMEN_RISS): Belt between
Combustion engine and starter generator torn
And/or one or more of the following other issues are also occurring:

Noise in the area of the belt drive.
Odor from the engine compartment.
Smoke formation in the area of the belt drive.
Drive belt damaged or prematurely worn.
Torn drive belt.

CAUSE
Slipping of the drive belt under certain operating conditions, especially in overrun (off throttle) operation at
low engine speed.

PROCEDURE
Proceed with the following stepsPerform diagnosis with ISTA and follow any test plans related to the FC and 48V system
Check the alignment marks on the belt tensioner

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12 07 21_B58C/D (48V SYSTEM): Belt Slip Fault 21B209

Black mark (1) on tensioner needs to be
centered in adjustment window (2)

Remove and visually inspect the drive belt (the belt will be replaced)
The drive belt may already show visible wear on the side with the ribs
The belt may be cut or missing ribs
There may be signs of oil contamination

The ribs may be narrower or worn thin
(1).

Using a mirror, check the index number of the crankshaft damper

Replace the damper if has an index
number 01

Inspect the pulley on the starter generator for tightness

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12 07 21_B58C/D (48V SYSTEM): Belt Slip Fault 21B209

Check the retaining screw (1) for the
hexagon nut (2) on the SGR drive pulley.

If the retaining screw is loose (finger tight) or missing, the starter generator must be replaced
If the retaining screw is tight – Check the pulley grooves for belt material and clean any debris
from the pulley with brake cleaner and a cloth rag (no wire brush)
Check that the SGR pulley spins freely. Take a video of any binding of the pulley
Check the pulley on the water pump
Check for binding in the pump and ensure the pulley spins true
Take a video of any issue with the water pump (if there is any) and replace the pump
AC Compressor - Check the pulley grooves for belt material and clean any debris from the
pulley with brake cleaner and a cloth rag (no wire brush)
If there is any issue with the AC compressor or the pulley (damage or leaking), replace the AC
compressor
Example: Belt debris in pulley
grooves (1).

PARTS INFORMATION
Obtain and confirm the part numbers for your specific vehicle by entering the chassis number in either ETK
or AIR which takes into account specific equipment and/or options.
Part Number
11 28 9844643
11 23 9845162
11 28 7952899
about:blank

Description
Quantity
Ribbed v-belt (6PKx1196 (48V))
1
Vibration Damper
1
48V Mechanical
belt
tensioner
1
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11 23 8585220
11 11 8664905

12 07 21_B58C/D (48V SYSTEM): Belt Slip Fault 21B209

ASA-Bolt (M10x65)
Shaft seal (55x68x8)

4
1

CLAIM INFORMATION
Covered under the terms of the BMW New Vehicle Limited Warranty for Passenger Cars and Light Trucks.
Defect Code:

1128026900

Ribbed V-belt, main drive Worn / sheared through

Refer to AIR for the corresponding flat rate unit (FRU) allowances.
Labor Operation

Description

Labor
Allowance

00 00 006

Performing vehicle test (with vehicle diagnosis
system – checking faults) (Main work)

Refer to AIR

Performing vehicle test (with vehicle diagnosis
system – checking faults) (Plus work)

Refer to AIR

Support voltage of the vehicle electrical system /
recharge vehicle electrical system battery

Refer to AIR

Performing vehicle diagnosis – test module

Work time (WT)

Diagnosis Worktime Flat Rate (See below)

2 FRU

Removing and installing/replacing drive belt for
starter motor generator

Refer to AIR

11 28 940

Additional work with replacing drive belt for starter
motor generator (Associated work)

Refer to AIR

Or:
11 23 510
And:

Removing and installing/replacing vibration damper

Refer to AIR

11 99 000

Work time for inspecting and cleaning pulleys on
drive belt components (3 FRU) and in conjunction
with 1128 575 and 11 28 940 or 11 23 510, the
additional work for replacing belt tensioner for drive
belt of starter motor generator (3 FRU)

6 FRU

Or:
00 00 556
And:
61 21 528
And, as necessary:
61 00 006*
Or
00 58 500*
And:
11 28 575
And:

If you are using a Main labor code for another repair, use the Plus code labor operation 00 00 556 instead of
00 00 006, or exclude (including 61 21 528) when the Vehicle Test is included in another repair.
Additional/Other Repair Work
If additional and/or other covered repair work is performed after carrying out the ISTA diagnostics and the
related test plans, claim this additional work with the defect code listed above or with the one in AIR that
applies. Also include any other necessary labor operations that also apply (with the overlapping labor
removed) including the diagnosis that applies*.
*Based on which one applies to your center, please refer to SI B01 01 20 or B01 07 20 for the applicable
procedure for documenting, claiming, and explaining, on the RO and in the claim comments, your diagnosis
work time (WT), job/repair work time (WT), and the vehicle repairs your center performed, unless otherwise
required by State law.

FEEDBACK REGARDING THIS BULLETIN

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12 07 21_B58C/D (48V SYSTEM): Belt Slip Fault 21B209

To submit feedback for the technical topics of this bulletin: Submit your
feedback in the rating box at the top of this bulletin
To submit feedback for the CLAIMS section of this bulletin: Submit an IDS
ticket to the Warranty Department, or use the chat available in the
Warranty Documentation Portal
To submit feedback for the PARTS section of this bulletin: Submit an IDS
ticket to the Parts Department

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12 07 21_B58C/D (48V SYSTEM): Belt Slip Fault 21B209

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