DTNA Solutions > Service Solutions > ‘ Freightliner
> SS 3124 - FTL Legacy M2 Bulkhead Module (BHM) Repl...

SS 3124 - FTL Legacy M2 Bulkhead Module (BHM)
Replacement and DiagnosticLink Issues 8

Applicable Vehicles

Legacy M2 Business Class, 108SD, 114SD using a Bulkhead Module (BHM) and Chassis Module (CHM)
for power distribution and control.

Production vehicles may have used any of approximately 10 different part numbers.

Currently-available replacement BHM parts include:

1. 06-75157-001 ("pre-2016 OBD"), version 7.30 software

2. A66-03086-001 (automatic baud rate detection for J1939), version 7.43 software
3. A66-03086-002 (fixed 250kbps J1939 baud rate), version 7.45 software

4, A66-03086-003 (fixed 500kbps J1939 baud rate), version 7.44 software

Symptoms

After replacing the BHM in a truck without first confirming the correct part with Excelerator,
DiagnosticLink may not be able to program the replacement BHM. Although DiagnosticLink may
report success, the VIN in the replacement part is (usually) the "blank" VIN of
ABCDEFGHIJKLMNOP1.

If an incorrect part is used, and then the correct part is installed, DiagnosticLink may program an
incorrect software version to the module. See the attached screen shot, which shows the
DiagnosticLink Professional view of a BHM with part number 06-75157-001 (originally loaded with
7.30 application software) that was reflashed to 7.45 application software and has a blank VIN.
Flashing to a different software version than supported by the module may render a BHM
inoperative. The example noted above resulted in a module that would only communicate ona
500kbps J1939 network, where the truck had a Natural Gas engine that only supported a 250kbps
J1939 network.

NOTE: There are other known situations where a replacement BHM cannot be programmed. If the
replacement part was confirmed before any programming attempt, this Service Solution likely will

not apply.

Issue

When replacing the BHM, Excelerator mustbe consulted to determine the correct replacement
part for the serial number that is being serviced.

This is especially important if a truck is being rebuilt with a sales cab. Sales cabs may not have the
correct BHM for the original vehicle. Use the serial number of the original vehicle when confirming
the correct BHM part number.

If an incorrect BHM (per the pats catalog) is used, there are several issues that arise when using
DiagnosticLink Professional to configure the BHM:

1. DiagnosticLink Professional will not flash the per-serial configuration to the module, as noted
above.

2. As aresult of the failure to flash the per-serial configuration, the VIN in the BHM will remain at
"ABCDEFGHIJKLMNOP'".

3. DiagnosticLink will attempt to migrate the vehicle data to an (incorrect) software version.

. Without further intervention by the DTNA CAC, further attempts to install a BHM will also fail.

5. Even if the correct BHM part is subsequently installed, DiagnosticLink professional will
reprogram the application software, rendering the BHM unusable except on newer M2
chassis.

>

At least two instances where a dealer has rendered multiple BHM parts unusable have been
reported.
Sometime after calendar year 2017, three different BHM "upgrade" paths were defined. Prior to that
time, any BHM with newer software cou/dbe installed on an older truck without issue. That is no
longer true - the following defined "breakpoints" for BHM software and parameter compatibility are
enforced in the FLT mainframe. However, these breakpoints are not correctly enforced with
DiagnosticLink.

1. BHM 7.30 software is compatible with a//M2 chassis built before 2016 OBD changeover (2
January 2016) for the U.S. and Canada, and may have also been used on vehicles for export
markets. See below for more information. Part number 06-75157-001 replaces all M2 BHM
parts for older M2 chassis.

e Allolder M2 chassis canbe updated to the 7.30 software without issue. Parameter
interchange and compatibility has been confirmed.

e There is no upgrade pathto newer software versions (7.4x) - parameter interchange and
compatibility is not defined.

2. BHM 7.43 software is compatible with approximately the first 2 years of 2016 OBD production
(2 January 2016 changeover). New module part number is A66-03086-001.

e Version 7.45 software can be flashed to a BHM that has 7.41 software without any loss of
functionality.

e Although theoretically possible, upgrades to either the 7.44 or 7.45 software
are blocked because the boot loader

5. BHM 7.45 software was changed over on 18 January 2021 and is compatible only with M2
chassis built for export markets or with an engine exempt from HD-OBD regulations. Part
number A66-03086-002.

e Trucks witha 7.41lor 7.43 Bulkhead Module and a 250kbps J1939 datalink CANNOT be
updated to this software version. The application is not compatible with the boot loader
used on earlier modules and upgrades are blocked.

e This software is not compatible with trucks that used BHM 7.30 or earlier software.

e This software is not compatible with trucks that used BHM 7.44 software, the BHM will
prevent communication on the J1939 network.

4. BHM 7.44 software was changed over on 18 January 2021 and is compatible only with M2
chassis built after that date. This version is a fixed 500kbps baud rate J1939 module, intended
to address some of the issues caused by the automatic baud rate detecting modules
(versions 7.41 and 7.43). Part number A66-03086-003.

e Trucks with 7.41 or 7.45 software and a 500kbps J19359 datalink CANNOT be updated to
this software version.

e DiagnosticLink may offer software version 7.44 as a software upgrade. Efforts are
underway to prevent this from occurring.

e The 7.44 application software is not compatible with the boot loader used on the
7.41 and 7.43 version BHM modules.

e This software is not compatible with trucks that used BHM 7.30 or earlier software.

e This software is not compatible with trucks that used BHM 7.45 software, the BHM will
prevent communication on the J1939 network.
NOTE: the 2 January 2016 changeover date represents the date when the automatic baud rate
detecting BHM (version 7.41) changed over in production for trucks that complied with the 2016 HD-
OBD regulation changes for the U.S. and Canada. Some trucks built in 2016 may have used the
version 7.30 fixed baud rate module, therefore, this is notan "absolute" date. Vehicles built for
Mexico and export markets did not adopt a 500kbps J1939 datalink at the same time, and BHM
version 7.30 remained in production until July 2017. Excelerator will list the correct BHM
replacement for each truck serial number.

Solution

Before using DiagnosticLink, ensure that the correct BHM part number, as called out in
Excelerator, is installed on the truck. Excelerator has correct part number information for the BHM
(module 32A).

If a module has been replaced, and it is determined that the module was flashed with incorrect
software, DiagnosticLink has initiated a data migration. A ticket must be logged with the Customer
Assistance Center in SalesForce, specifically requesting BHM migration rollback.

Labels :

(108sp ) (1msp ) (Electrical ) (wz )

Add tags

Attachments

4

5 Kudos

Comment

Powered by

Khoros <
BHM_J1939 - Bulkhead Module

Device Configuration
Software Mode Running in Application

Device Information

Make FRGHT

Model BHM_L

Serial Number 504055

Hardware Revision AO

Software Indentification U.r.2.A0.07.45

VIN ABCDEFGHUKLMNOP1
ID Block

Diagnostic Version 745

' sean BH
li ig = 4
“tn Lo

JOHN BEEHEE ELECTRO

=O,