SUBJECT:

No:

LOUD ELECTRIC COMPRESSOR SOUND
WHILE USING HEATER - REVISED

DATE:

TSB-23-55-007REV
April 2024

MODEL:

See below

CIRCULATE TO:

[ ] GENERAL MANAGER

[ X ] PARTS MANAGER

[ X ] TECHNICIAN

[ X ] SERVICE ADVISOR

[ X ] SERVICE MANAGER

[ X ] WARRANTY PROCESSOR

[ X ] SALES MANAGER

This bulletin supersedes TSB-23-55-007 dated November 2023 to update the affected
vehicles. Revisions are italicized and indicated by ◄.

PURPOSE

This reflash corrects the rotational speed of the electric compressor to reduce a loud highfrequency operating noise during use of the heater when a vehicle is stationary.

BACKGROUND

The heat pump and air conditioner operate an electric compressor to raise the water
temperature. When the water temperature is low, the electric compressor operates at high
speed, which can temporarily increase the operating noise.
Upon customer complaint, please reprogram the PHEV A/C amplifier control program (HVAC2)
with the countermeasure software to reduce the loud high-frequency noise.

AFFECTED VEHICLES

2023-2024 Outlander Plug-in Hybrid built before VIN JA4T5WA90RZ021996 and 4/10/2023

REPROGRAMMING CAUTIONS
Caution during reprogramming:
 Turn off all electrical devices to minimize the vehicle's electrical load. Also use an external power
source to ensure that the vehicle battery maintains the specified voltage during reprogramming.
The low voltage of the auxiliary battery may cause the incompletion of reprogramming and once
it happens, ECU must be replaced with a brand new one.
 Write down all the customer’s electrical device settings such as A/C and radio before
reprogramming and restore them after reprogramming.
 Connect the MUT-3 to an AC power source to prevent internal battery discharge.
 Before using, make sure the USB cable and MUT-3 main harness are not damaged.
 Do not perform maintenance work in the engine room during reprogramming
The cooling fan may operate while reprogramming.
 Check the All DTC after reprogramming and if any, erase them.

Copyright 2023, Mitsubishi Motors North America, Inc.
The information contained in this bulletin is subject to change. For the latest version of this document, go to the
Mitsubishi Dealer Link, MEDIC, or the Mitsubishi Service Information website (www.mitsubishitechinfo.com).

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EQUIPMENT
•
•
•
•
•
•
•

The following equipment is needed to reprogram the HVAC2
VCI (Vehicle Communication Interface) or VCI Lite - MB991824 or MB992744
MEDIC Laptop/Tablet with A/C power adapter - 520924, or FZG1MK2
MUT III Main Harness "A" (blue connector at the DLC end) - MB991910 or MB992745
USB 2.0 Cable - MB991827 or MB992747
MEDIC 3.5/4 update at 830 or higher
For Standalone MUT III units, MUT3-SE Reprogramming Database N230901NR or higher

ECU REPROGRAMMING CHART
Model

Data No.

Outlander
PHEV

27531W01.1PN

New HW
Part No.

New SW Part
No./Ver.

Target HW
Part No.

27531W011P

Target SW
Part No./Ver.

Remarks

27531W002P

23-24MY

REPAIR PROCEDURE
SOFTWARE/MEDIC VERSION VERIFICATION
1. Verify that the HVAC2 has not already been updated to the latest S/W number in the table
above. If the HVAC2 is at the latest level, reprogramming is not necessary.
NOTE: Reprogramming the target HVAC2 with the latest database (e.g.,
N230901NR includes all past and current reprogramming for TSBs of affected
vehicles. It is not necessary to reprogram the HVAC2 for each previous TSB.

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For MEDIC 3.5/4 users only: (MUT-III SE users go to step 5)
2. Verify the MEDIC 3.5/4 is at version 3.5/4 and at update 830 or higher.
If your MEDIC 3.5/4 update is at least 830 continue with the Reprogramming Procedure. If
your MEDIC 3.5/4 update is below 830, update your MEDIC as follows.

3. Select the MEDIC 3.5/4 Admin tab and click on “Updates”.

4. If the MEDIC update screen advises updates are available, click the “Begin” button.
After all updates are complete, GO TO THE REPROGRAMMING PROCEDURE.

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5. Click “STV”.

a. Confirm the vehicle information is accurate, select HVAC2 and click the OK button.

b. Click “ECU Reprogramming (SDB) and press the OK button”.

c. Select “Reprogramming (ECU software rewriting)" click the OK button.

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d. Confirm that the database number displayed is N230901NR or higher.
i. If the database number displayed on your MUT3-SE is N230901NR or greater,
continue to the next section.
ii. If the reprogramming database number displayed on your MUT3-SE is lower than
N230901NR, then the MUT3-SE database needs to be updated.
iii. Confirm the New HW Part No., click in the selection box and press the OK
button.

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REPROGRAMMING PROCEDURE
To ensure that the vehicle battery maintains 12V during the procedure,
hook- up a battery charger to the vehicle during the procedure.
NOTE: VCI Stand−alone reprogramming is not available for this procedure. The laptop/tablet
and the VCI must remain connected for the entire procedure.
1. Connect the equipment as follows:
NOTE: VCI Lite and MEDIC 4.0 Toughpad shown for illustration purposes only.

Data Link
Connector (Blue
End)
MUT−III SE
Main Harness

•

Turn the MEDIC PC/tablet on. If the battery
indicator in the lower right hand corner of the
screen does not show a full charge, it is
recommended that either the battery be
charged prior to beginning or be used with the
A/C power adaptor connected.

•

Connect the USB cable to the VCI/VCI Lite. When
the laptop/tablet displays the MUT-III SE main
screen, connect the USB cable to the device.
Connect the MUT-III SE main harness with the
blue DLC connection to the VCI/VCI Lite. Connect
the blue connection of the MUT-III SE main
harness to the vehicle's data link connector.

•
USB Cable
Toughpad
(back)

VCI Lite

•

For VCI only (p/n MB991824): Turn the VCI
power switch ON. Verify that the indicator
lamp in the upper right corner of the screen is
green.

DO NOT DISTURB THE HARNESS CABLES OR CONNECTIONS DURING THE REPROGRAMMING PROCESS
AS IT COULD CAUSE THE CONTROL UNIT TO LOSE DATA. IF THE USB CABLE IS DISCONNECTED
DURING THIS PROCEDURE, A WARNING MESSAGE WILL DISPLAY.
NOTE: Due to limited space it may be easiest to connect cable onto negative ground post
and ground strap as shown below.
2. Turn the ignition switch to the “ON”
position.

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3. Using MEDIC, from the main page, click the
“MUT3-SE” icon at the top center of
the screen.

4. The System Select screen opens and populates
with some basic information from the vehicle.
Look at the label on the passenger side B pillar
to identify the appropriate class. (See B pillar
label below; class is labeled as “model”). If
necessary, select the correct class from the
drop-down list.

*Image for illustration purposes only

5.

Verify that the ECU has not already been updated to the latest S/W number shown in the
“ECU Reprogramming Chart” in this TSB. If the ECU is at the latest level, reprogramming is
not necessary. If reprogramming is necessary, proceed with the following steps.
a. Select ECU Reprogramming (SDB).

b. Select “HVAC2" in the System List and press the OK button.

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c. Select “Reprogramming (ECU software rewriting)" click the OK button.

d. Click the selection box and press the OK button. Reprogramming will begin and a progress bar
will appear followed by a notification upon successful completion.

e. Confirm the reprogramming results and press the OK button.

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f. Select ALL DTCs.

g. Select Erase and Read all DTCs.

h. Click the OK button to begin.

i. Results and a completion notification will be displayed.

j. If an active DTC is found after reprogramming, perform auto-configuration according to the
Service Manual, confirm DTC is no longer active and erase DTC's in all systems.

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6. Using a ball-point pen, enter the appropriate ECU part number, Software Part Number (ROM
ID#), this Technical Service Bulletin number, your dealer code, and the current date on
the Engine Compartment/Control Module Label (p/n MSSF024G00). The Vendor Code is
not applicable. The label is available from your facing PDC.

7. Test drive the vehicle to confirm proper operation.

WARRANTY
This bulletin is supplied as technical information only and is not an authorization to repair. If
an affected vehicle is reported with the described condition, diagnose the condition, repair as
described in this bulletin and submit a normal warranty claim using the information below.
Labor Op Code
558527MG

04/08/2024

Operation

Quantity

Work Time

PHEV A/C amplifier control program update

1

0.3H

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