Updating HVAC ECU Software to Fix Front HVAC
Evaporator Freezing and Improve Espar Heater Cool Down
FLA COE
FLB COE
FLD Conventional
Business Class
FLC 112 Conventional

Century Class Conventional
Argosy
Cargo
Columbia
122SD and Coronado

Business Class M2
Cascadia
108SD/114SD
> New Cascadia

54-338
Freightliner
Service Bulletin

Description of Revisions: This bulletin replaces the version dated
03/03/2021. Information on software versions and the number of
software updates needed has been updated.

General Information
New Cascadia vehicles with sleeper cabs may become extremely cold when in A/C mode, which can lead to
reduced airflow as a result of internal ice buildup at the evaporator.
Conditions that contribute to the front evaporator freezing include:
• Engine at 900 rpm and above, typically noticed when vehicle is moving at 60 mph (97 km/h) or more.
• Air conditioning in recirculation mode; the front evaporator may freeze in ECO mode but it will take much
longer.
• Blower motor operating at 50% power or above.
• Temperature control knob turned to the full cold setting.
• Ambient temperature approximately 86°F (30°C) or above.
• Humidity at 75% or higher.
There are also issues with the durability of the Espar D5 heater system when paired with the battery parked
HVAC system (BPHS). This can be improved by applying "cool down" software to the parked electronic control
unit (ECU) HVAC_P01T.
The front evaporator freezing issue is addressed by the new software available for the front ECU HVAC_F01T
and auxiliary ECU HVAC_R01T.
This software is now available and should be installed. The software is backwards compatible for all ECUs.
Each vehicle will require the software updates listed.
For vehicles without a BPHS or ParkSmart unit, install the software listed below. If a newer version of the
software listed is available, install that.
Software for Vehicles Without a BPHS or ParkSmart Unit
Controller
Flashware Item
Dataset Item
F01T
001 448 14 28 001
001 448 05 28 001
R01T
001 448 07 28 001
001 448 08 28 001
Table 1, Software for Vehicles Without a BPHS or Parksmart Unit

For vehicles with a BPHS, install the software listed below. If a newer version of the software listed is available,
install that.

Controller
F01T
R01T
P01T

Software for Vehicles With a BPHS
Flashware Item
Dataset Item
001 448 14 28 001
001 448 05 28 001
001 448 07 28 001
001 448 08 28 001
000 448 70 28 007
N/A
Table 2, Software for Vehicles With a BPHS

Freightliner Service Bulletin, 03/23/2021

Page 1

54-338

Updating HVAC ECU Software to Fix Front HVAC
Evaporator Freezing and Improve Espar Heater Cool Down

Freightliner
Service Bulletin

FLA COE
FLB COE
FLD Conventional
Business Class
FLC 112 Conventional

Century Class Conventional
Argosy
Cargo
Columbia
122SD and Coronado

Business Class M2
Cascadia
108SD/114SD
> New Cascadia

For vehicles with a ParkSmart unit, install the software listed below. If a newer version of the software listed is
available, install that.

Controller
F01T
R01T
P01T

Software for Vehicles With a ParkSmart Unit
Flashware Item
Dataset Item
001 448 14 28 001
001 448 05 28 001
001 448 07 28 001
001 448 08 28 001
000 448 68 28 003
N/A

Table 3, Software for Vehicles With a ParkSmart Unit

After the HVAC_P01T software has been updated, drivers may notice the Espar combustion chamber fan and
coolant pump running for approximately three minutes after the Espar D5 heater has turned off.

General Information
There are two different procedures for programming chassis ECUs with DiagnosticLink:
• Updating functioning vehicle chassis ECUs by uploading the parameters of the vehicle’s ECUs to the
server and then downloading these parameters with the updated software.
• Overwriting the parameters and software installed on the ECU with the most recent parameter sets and
software from the server by directly using ’Program Device.’
This service bulletin will use the second procedure to program the HVAC ECUs.

Procedure
1. Park the vehicle on a level surface, shut down the engine, and apply the parking brakes. Chock the tires.
2. Connect the vehicle to DiagnosticLink. Ensure DiagnosticLink is updated to the latest version (8.13 at the
time of publication) or newer. To update DiagnosticLink, select ’Tools’ from the top menu and then select
’Update’ from the dropdown menu. See Fig. 1.

Page 2

Freightliner Service Bulletin, 03/23/2021

Updating HVAC ECU Software to Fix Front HVAC
Evaporator Freezing and Improve Espar Heater Cool Down
FLA COE
FLB COE
FLD Conventional
Business Class
FLC 112 Conventional

Century Class Conventional
Argosy
Cargo
Columbia
122SD and Coronado

Freightliner
Service Bulletin

Business Class M2
Cascadia
108SD/114SD
> New Cascadia

01/15/2021

54-338

f120507

Fig. 1, Updating DiagnosticLink to the Latest Version

2.1

When programming, we recommend configuring DiagnosticLink to connect only to ’Default’ ECUs.
To make this change in DiagnosticLink:
• Select ’Tools’ from the top menu, and then select ’Options’ from the drop down menu.
• Find and select the ’Connection’ tab. See Fig. 2.
• Select the ’Select Defaults’ button on the right side of the window, then select ’Apply.’

Freightliner Service Bulletin, 03/23/2021

Page 3

54-338
Freightliner
Service Bulletin

Updating HVAC ECU Software to Fix Front HVAC
Evaporator Freezing and Improve Espar Heater Cool Down
FLA COE
FLB COE
FLD Conventional
Business Class
FLC 112 Conventional

Century Class Conventional
Argosy
Cargo
Columbia
122SD and Coronado

Business Class M2
Cascadia
108SD/114SD
> New Cascadia

1
2

3

02/01/2021

f120850

1. ’Connection’ Tab

2. ’Select Defaults’ Button

3. ’Apply’ Button

Fig. 2, Configuring DiagnosticLink to Connect to Default ECUs

3. Address any pre-existing conditions or fault codes.

NOTE: In DiagnosticLink an ECU is called a ’device.’
4. Select ’Program Device’ from the upper left-hand side of the window. See Fig. 3.

02/01/2021

f120466a

Fig. 3, Selecting Program Device (ECU)

Page 4

Freightliner Service Bulletin, 03/23/2021

Updating HVAC ECU Software to Fix Front HVAC
Evaporator Freezing and Improve Espar Heater Cool Down
FLA COE
FLB COE
FLD Conventional
Business Class
FLC 112 Conventional

Century Class Conventional
Argosy
Cargo
Columbia
122SD and Coronado

Business Class M2
Cascadia
108SD/114SD
> New Cascadia

54-338
Freightliner
Service Bulletin

5. Remove any ’Request Pending’ downloads and serial numbers in the main window by selecting the
’Request Pending’ list item(s) and then selecting the ’Remove’ button on the right-hand side of the window.
Do not select ’Remove All;’ selecting ’Remove All’ deletes all data pending upload. See Fig. 4.

02/04/2021

f120463a

Fig. 4, Removing Pending Requests

6. Use your DTNAConnect information to connect to the server. Your sign-in to the server will remain active
until DiagnosticLink is closed.
7. Select ’Add’ to add a download request for the vehicle by entering the vehicle identification number (VIN).
See Fig.5.

01/15/2021

f120841

Fig. 5, Adding the VIN to Download Updated Server Data

8. Make sure the correct VIN is populated in the window, then select ’OK.’ See Fig. 6.

Freightliner Service Bulletin, 03/23/2021

Page 5

54-338
Freightliner
Service Bulletin

Updating HVAC ECU Software to Fix Front HVAC
Evaporator Freezing and Improve Espar Heater Cool Down
FLA COE
FLB COE
FLD Conventional
Business Class
FLC 112 Conventional