2020 Mercedes Benz Truck ML 350 Technical Service Bulletin # S-15_40-58B Date: 110701
Charging System - Voltage Regulator, Inspection/Testing
Date: July 2011
Order No.: S-B-15.40/58b
Supersedes: S-B-15.40/58a (5/2007), S-B-15.40/58, P-B-15.40/56, T-B-15.40/57
Group: 15
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SUBJECT
Test and Inspection of Charging System Regulator
Revision History
Revision Date Purpose
B 07/2011 Added Model 240
A 03/07 Addition of models 164.122/822/871, 211.022,251.122,230, 463, and warranty coding information
- 05/05 Initial issue
During testing of returned alternators (that were replaced under warranty) it has been determined that many alternators are being replaced when only
the (replaceable) regulators are found to not be functioning. Therefore, in the event a charging system test determines the need to replace a
nonfunctioning regulator; replace the regulator (independently from alternator).
Note:
Regulators installed on water cooled alternators and those installed on model 199 alternators are not replaceable.
For regulator test and inspection instructions refer to Subject A.
A. Test and inspection of charging system regulators
1. Refer to Subject B for charging system testing instructions.
2. For instructions on replacing nonfunctioning regulators for models:
^ 163 refer to Subject C
^ 203 4Matic, 211 4Matic, 215, 220, 463 refer to Subject D
^ 203/208/209/211/219/230 refer to Subject E (does not include 4Matic models).
^ 129/164/170/171/202/210/221/251, and models not listed above (that are included in this Bulletin) refer to WIS group: 15.40.
Note:
(when referring to WIS instructions for replacing regulator)
Ensure non functioning regulator is inspected (refer to Subject F, step 3) prior to replacing.
Ensure circuit 30 systems are reinitialized and fault codes are erased (refer to refer to Subject F, steps 8 and 9).
3. After removing a regulator that has been tested and found to be not functioning, it must be visually inspected (refer to Subject F, step 3) to
determine the condition of the alternator bearing.
B. Alternator Diagnosis
Some of the engines in the above model vehicles are equipped with alternators which communicate with the ME or CDI engine control via an
interface. This has resulted in changes to both system diagnosis and testing the alternator. A distinction is made between a conventional alternator
with terminal 61 without an interface and alternators with a BSS or LIN interface. This section of bulletin describes the different alternator types and
diagnostic abilities via STAR Diagnosis.
Alternator Types
1. "CONVENTIONAL" alternator not linked to the engine control module (ECM)
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^ No form of communication between the alternator and engine control module
^ Engine control module cannot assist during the alternator test
^ Testing not possible with STAR Diagnosis, only with a traditional Volt-Ampere-Tester
2. "BSS" alternator linked to the engine control module per BSS
^ BSS = Bit Synchronous Interface, communication is one-way from engine control module to alternator.
^ Testing possible via engine control module and STAR Diagnosis.
3. "LIN" alternator linked to the engine control module per LIN
^ LIN = Local Interconnect Network, communication is two-way between engine control module and alternator.
^ Testing possible via engine control module and STAR Diagnosis
Note:
Alternators with a BSS or LIN interface have greatly enhanced diagnosis capabilities. BSS or LIN interfaces allow these alternators to be tested with
STAR Diagnosis and without the use of an external tester. STAR Diagnosis detects whether a BSS interface or an LIN interface is present when
communicating with the engine control module.
The following is an overview of the engine model designations with their corresponding alternators:
Current overview of engines on which the alternator test can be carried out with STAR Diagnosis as of the approval date stated:
The test step is listed as "Alternator Diagnosis" in STAR Diagnosis and can be found in the following locations:
^ CDI engine control module under "Actuations"
^ ME engine control module under Complete list of guided tests, and as of STAR Diagnosis-DVD 01/2006 also under "Actuations".
Note:
The following notes should be adhered to when testing an alternator with STAR Diagnosis
^ The test prerequisites for the alternator test are listed in the DAS and must be observed. The test itself is arranged as a test sequence and is
menu-assisted.
^ During the process it should be noted in particular that the upper limit value of the regulation voltage can now be up to 15 Volts. Refer to the
current documents in the workshop literature for the valid specified values.
^ Future engine model designations will also be equipped with these interfaces and this document will be updated to reflect these additions as this
occurs.
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^ All alternators which do not have a BSS or LIN interface cannot be checked with STAR Diagnosis. For this generation alternator, continue to test
with traditional Volt-Ampere-Tester. Refer to the current documents in WIS group 15.40 for the valid specified values.
^ The specified values have been updated for charging current and regulation voltage for all alternators.
C. REMOVE REGULATOR WITH ALTERNATOR FROM ENGINE COMPARTMENT MODEL 163
Remove alternator from vehicle (refer to WIS: AR15.40-P-5032GH) then proceed to Subject F, Inspect and Replace Regulator.
D. REMOVE REGULATOR WITH ALTERNATOR IN ENGINE COMPARTMENT MODELS 203 4Matic, 211 4MATIC/215/220/463
Note:
^ Model 463: Proceed to step 1.
^ Models 203 4Matic/211 4Matic/215/220:
Proceed to step 2
1. Model 463:
^ Disconnect battery ground cable from battery terminal.
^ Remove right air intake duct (arrow, Figure 1).
^ Remove front section of upper engine cover (A, Figure 1).
^ Remove engine fan refer to WIS: AR20.40-P-5660C.
^ Remove engine belt from alternator pulley (do not remove belt from vehicle) refer to WIS: AR13.22-P-1202B
Note (regarding above WIS instructions):
When removing engine belt from alternator pulley, do not remove fan shroud.
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^ Remove upper alternator mounting bolt (B, Figure 2).
^ Loosen lower alternator mounting bolt (A, Figure 2) from mounting bracket (arrow).
^ Disconnect circuit 61 harness connector (arrow, Figure 3) from regulator.
^ Remove circuit 30 terminal cover (A)
^ Remove nut (arrow, Figure 4) then remove circuit 30 harness connector (A) from terminal stud.
^ Remove lower alternator bolt (A, Figure 2) from mounting bracket.
^ Remove alternator (B, Figure 4) from mounting brackets.
Note:
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Do not remove alternator (B) from engine compartment.
^ Position alternator (A, Figure 5) with regulator facing up and pulley facing down. Regulator will be replaced with alternator in engine
compartment (proceed to Subject F).
2. Models 203 4Matic/211 4Matic/215/220:
^ Disconnect battery ground cable from battery terminal.
^ Remove right air intake duct (arrow, Figure 6).
^ Remove front section of upper engine cover (A, Figure 6).
^ Models 215/220 AMG (supercharged) only:
^ Remove supercharger belt from vehicle refer to WIS: AR13.21-P-1202RVK.
^ Remove cap (arrow, Figure 7) on idler pulley (A).
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^ Remove idler pulley bolt (arrow, Figure 8) and idler pulley (A).
Installation Note:
When reinstalling, torque bolt (A) to 68 Nm.
^ Remove engine belt from alternator pulley (do not remove belt from vehicle) refer to WIS: Group 13.22
^ Model 203 4Matic/211 4Matic only: Unclip heater hose (A, Figure 9) from mounting clip (arrow).
^ Disconnect circuit 61 harness connector (arrow, Figure 10) from regulator.
^ Raise vehicle on vehicle lift then remove lower (center) engine cover.
^ Remove circuit 30 terminal cover (A, Figure 10).
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^ Remove nut (arrow, Figure 11) then remove circuit 30 harness connector (A) from terminal stud on alternator (B).
^ Loosen upper alternator mounting bolt (B, Figure 12).
^ Remove lower alternator mounting bolt (A), then remove upper alternator mounting bolt (B).
^ Remove alternator from mounting brackets.
Note:
Do not remove alternator from engine compartment.
^ Position alternator (A, Figure 13) with regulator facing up and pulley facing down. REGULATOR WILL BE REPLACED WITH
ALTERNATOR IN ENGINE COMPARTMENT (proceed to Subject F).
Note:
Coolant hose (Figure 12) is repositioned for clearance. Return hose to installed position after reinstallation.
E. REMOVE REGULATOR WITH ALTERNATOR BOLTED TO ENGINE MODELS 203/208/209/211/219/230
Note:
Subject E does not apply to 4Matic models.
1. Disconnect battery ground cable from battery terminal.
2. Raise vehicle.
3. Remove lower engine cover:
^ Models 211/219/230: Remove lower middle engine cover.
^ Models 203/ 208/ 209: Remove (single) lower engine cover.
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4. Disconnect circuit 61 connector (arrow, Figure 14) from regulator.
5. Remove circuit 30 cover (A, Figure 14) from terminal.
6. Remove nut (arrow, Figure 15) then remove circuit 30 harness connector (A) from terminal stud on alternator (B).
7. Replace regulator with alternator bolted to engine (proceed to Subject F).
F. INSPECT AND REPLACE REGULATOR
Note:
Regulator replacement procedure below applies to Bosch alternators. For regulator replacement procedure on alternators from other manufacturers
refer to WIS group: 15.40.
Note (when refering to WIS instructions for replacing regulator):
^ Ensure malfunctioning regulator is inspected (refer to step 3 of this section) prior to replacing.
^ Ensure circuit 30 systems are reinitialized and fault codes are erased (refer to steps 8 and 9 of this section).
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1. Remove the two nuts (1, Figure 16, 17) from studs and one Philips head screw (2); remove the plastic cover from the rear of the alternator.
Note:
Observe which nut is removed from either stud.
2. Remove three Philips head screws (2, 3, Figure 17); remove voltage regulator (1) from the alternator.
3. Inspect wear shape (arrow, Figure 18) of carbon brushes:
If brushes have worn at an angle (arrow), alternator bearing damage is indicated and the alternator must be replaced. If brushes wear is normal,
continue with regulator replacement.
Note:
Minimum regulator brush dimension (A, Figure 19) = 5 mm.
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4. Install new voltage regulator (1, Figure 20) and torque Philips head screws to:
^ (2) = 2.0-2.4 Nm
^ (3) = 1.0-1.4Nm
Caution!:
Ensure the carbon brushes (arrows, Figure 21) are not damaged during the installation procedure.
5. Install the plastic cover on the back of the generator and torque the Philips head screw (2, Figure 16) to: 2.2 - 2.6 Nm and the two nuts (1, Figure
16) as follows:
^ On long stud: 29.0 - 32.0 Nm
^ On short stud: 11.0 - 13.0 Nm
6. Reinstall the alternator in reverse order
7. Reinstall components in reverse order.
8. Reconnect battery cable to negative battery terminal, reinitialize vehicle systems (e.g., steering angle sensor, power windows etc.); refer to WIS:
AR00.19-P-0200P.
9. Connect SDS and erase any faults that may have been stored.
Note:
Refer EPC for replacement part numbers.
NOTE:
The following allowable labor operations should be used when submitting a warranty claim for this repair.
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