BULLETIN NOTES
This Service Alert supersedes the previously issued SA(s) listed below. The changes are noted in Red.
Previous SAs:

Date(s) Issued:

SA-077/24

10/23/24

APPLICABLE MODEL(S)/VINS
2025 CX-50 HYBRID
DESCRIPTION
The CX-50 Hybrid has new and revised features that are different from previous models, and may be difficult to
understand. This Service Alert provides valuable information to support potential dealer and customer concerns.
Index
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PDI Fuse
Hybrid System Outline
Shutdown of High Voltage
Inspection Mode
Fuel Tank Interference with Flat Lift
12V Lead-Acid Battery with Port Plug
Compressor Oil (POE) for Electric A/C Compressor
PCU (Power Control Unit) Assembly
New 2.5L Engine (CW)
Front Transaxle Assembly
Rear Transaxle Assembly
Closed Fuel Tank
Electronically Controlled Brake System
High Voltage Battery
lnner Service of High Voltage Battery
Coolant Drain and Replacement
Towing
Jump Start Function
Tire Changing Machine
Shift Mechanism
Maintenance Notification

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Item

Service Information

PDI Fuse
Fuse F34 (25A) is removed from the engine compartment fuse block and is stored on the
engine compartment fuse block lid. Insert the fuse during PDI.

RELAY AND FUSE
BLOCK [00F-1]

Hybrid System Outline
• Hybrid vehicles use a combination of 2 kinds of power sources, such as an engine and
high voltage battery, to take advantage of the benefits provided by each power source
while compensating for each other's shortcomings. As a result, efficient operation is
achieved with higher gas mileage than a gas engine only.
• Hybrid vehicles do not need their batteries to be charged by plugging in, unlike existing
electric-only vehicles. They are charged from regenerative braking and the gas engine. HYBRID SYSTEM
• Technical development of power sources (such as engines and fuel cells) is advancing OUTLINE
in various fields. The hybrid system is a flexible system that uses a high-efficiency
power unit and electric motors.
• Hybrid vehicles have high-voltage electrical circuits and have been developed with
consideration given to the protection of drivers and technicians against electrocution.
• This hybrid vehicle uses THS-II to drive the front wheels and adds the e-AWD system
to drive the rear wheels.

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*1 Engine
*2 Hybrid transaxle
*3 Motor generator No.1 (MG1)
*4 Motor generator No.2 (MG2)
*5 Power split planetary gear unit (compound gear unit)
*6 Motor speed reduction gear unit (compound gear unit)
*7 Inverter with converter assembly
*8 High voltage battery
*9 Rear drive unit (rear traction motor with transaxle assembly)
*10 Rear motor (MGR)
Electrical power path (DC)
Electrical power path (AC)
Mechanical power path
Shutdown of High Voltage before High Voltage Service
Service Plug Removal
1. Verify that the READY indicator on the instrument cluster is not illuminated. If the READY
indicator is turned on, switch the main power OFF.
2. Disconnect the negative lead-acid battery terminal. Go to MGSS [NEGATIVE BATTERY
TERMINAL DISCONNECTION/CONNECTION].
3. Remove the rear seat lower trim grille. Go to MGSS [REAR SEAT LOWER TRIM GRILLE
REMOVAL/INSTALLATION].
4. Wear insulating gloves and remove the service plug using the following procedure.
a. Remove the service plug shown in the figure.

HIGH VOLTAGE
SERVICE CAUTIONS

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1) Pull out the lever in the downward direction.
2) Rotate the lever 90° in the direction of the arrow and press the lever until it
stops rotating.
3) Remove the service plug.
b. Verify that the service plug is removed.
c. Verify that the main power is switched OFF.
d. Leave the vehicle for 10 minutes.
NOTE: When the power supply is cut off, the electrical charge remaining in the
condenser is automatically discharged.
e. Remove the bracket (AWD).

A: Bracket
B: Bolts
C: Nut
f. Move the lock lever as shown in the image and disconnect the PCU connector.

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g. Remove the cover.

h. Measure the voltage between terminals P and N using a high voltage tester.
Standard Voltage: 0 V
NOTE: The tester display may not be 0 V depending on the measurement accuracy or
variations in the tester used.

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i Install the cover.
1) Install bolt "A" (*a)
Torque: 32-47 in·lbf (3.6-.4 N·m, 37-55 kgf·cm)
2) Install bolt "B" (*b)
Torque: 57-84 in·lbf (6.4-9.6 N·m, 66-97 kgf·cm)

Service Plug Installation
CAUTION: Before connecting the service plug, check the tightness of the high voltage
terminals and the connection status of the connectors.
1. Wear insulating gloves and install the service plug using the following procedure.

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a. Install the service plug straight into the socket with the lever in the upright position.
b. Rotate the lever 90° in the direction of the arrow and press the lever until it stops
rotating.
c. Press the lever in the direction of the arrow until it locks.
2. Install rear seat lower trim grille. Go to MGSS [ REAR SEAT LOWER TRIM GRILLE
REMOVAL/INSTALLATION].
3. Connect the negative lead-acid battery terminal. Go to MGSS NEGATIVE BATTERY
TERMINAL DISCONNECTION/CONNECTION
Inspection Mode
When engine running/idling is required for diagnosis – switch to Inspection Mode.
MAINTENANCE MODE
[CW]

• AWD MAINTENANCE MODE (4WD for measuring Exhaust Gas)
• AWD CERTIFICATION MODE (4WD for cutting TR(A)C)
Fuel Tank Interference with Flat Lift
Ni-Hydride Battery (Ni-MH Battery Pack (A): 245 volts, named High Voltage Battery) is laid
out under the rear seat, and then the fuel tank (B) is laid out under the Battery.

---

When trying to use a flat lift, there is a concern for deformation or breakage at the fuel tank
due to interference with the plate of the lift. Make sure to use an attachment of 120 mm
height such as Round Rubber Adapter for 3-stage arm lifts (39-FJ6202) (C) when using the
lift. Refer to the Workshop Manual on MGSS for detailed procedures.

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12V Lead-Acid Battery with Port Plug
The 12V lead-acid battery (A) is located in the trunk room as shown in the image and has a
port plug (Ventilation Type Calcium Battery).

---

(View from Center to Right side of Cargo Room.)
The required specifications are EN (European Norm) LN2(STD) with Port Plug 12v-55Ah/
20HR, CCA 345A or more.
Compressor Oil (POE) for Electric A/C Compressor
This hybrid model has an electric A/C compressor that requires Polyolester ND-11 (POE) Oil
due to the electrical insulation performance. Polyalkyleneglycol (PAG) Oil (such as E 1 Y061-K39) cannot be used in this electric A/C compressor.
Use only Mazda Genuine POE Oil (B4YL-61-K39 : DENSO ND-OIL 11) for the electric A/
C compressor.
CAUTION: Using any POE Oil other than the Mazda Genuine POE Oil may cause electric
leakage, deteriorated A/C performance, or damages on A/C components. KRYP-61-K39 of
A/C COMPRESSOR
RBl00EV-01 ENEOS (JXTG) for CX-90 and CX-70 PHEV model cannot be used in this
REMOVAL/
hybrid model.
INSTALLATION
NOTE: A properly adjusted amount of fluorescent agents is used during vehicle production.
Never add fluorescent agent into the refrigerant system, otherwise the insulation performance
may deteriorate. Never use A/C refrigerant gas containing A/C compressor oil and
fluorescent agent, or A/C compressor oil with fluorescent agent.
Refer to the Workshop Manual on MGSS for the detailed procedure.
NOTE: Removing the A/C compressor requires shutdown of the High Voltage as shown in
Shutdown of High Voltage before High Voltage Service.
PCU (Power Control Unit) Assembly
PCU (POWER
The PCU consists of the Motor Generator ECU (Electric Control Unit), Booster Converter,
CONTROL UNIT)
Inverter, DC-DC Converter, which needs to be replaced by an assembly (PCU Assembly: 30- REMOVAL/
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310)

INSTALLATION

A: Coolant IN
B: Coolant OUT
*1: Boost Converter / Inverter
*2 DC-DC Converter / Reactor
The PCU Assembly is cooled by coolant (FL22) in the Low Temperature (LT) line separately
from the High Temperature (HT) line which is cooling the engine (CW) also by coolant
(FL22).
Implement the initialization for the resolver (rotation angle sensor to control the motor) when
replacing the PCU using M-MDS. Refer to the Workshop Manual on MGSS for more details.
New 2.5L Engine (CW)

MECHANICAL

1) Use Mazda Genuine Engine Oil 0W-16 (ILSAC GF-6B) for the hybrid system available at
Mazda Authorized Dealers due to the certification.
NOTE: 0W-16, GF-6B is usable as alternative in addition to the above setting of Genuine Oil
at Dealers.
2) The following Tools and Equipment are required: Engine Hanger and Engine Lift Table
with attachments such as PLA-15 to avoid damaging the engine oil pan.
3) Use Mazda Genuine Spark Plugs (CWA 1-18-110 equals FC16HR-Q8/DENSO).
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New Front Transaxle Assembly (TPVA-E)
A newly developed Front Transaxle Assembly unit (A) is installed in this model, which
includes two Motor Generators (MG1 for charging Ni-MH Battery and supplying electrical
power to drive the front wheels and MG2 to assist engine output), and an ATF oil cooler
cooled by water (Low Temperature (LT) line).

Use only genuine ATF WS JWS3324 Automatic Transaxle Fluid (full level is approximately
4.1 quarts (3.9L) as shown).
COMPOUND GEAR
UNIT [TPVA-E]

B: Filler Plug
D: 0 - 0.4 in (10mm)

B: Filler Plug
C: Drain Plug
This new Front Transaxle Assembly unit needs to be replaced as a complete unit (19-090).
Implement the initialization for the resolver (rotation angle sensor to control the motor) using
M-MDS when replacing the Front Transaxle Assembly.
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Refer to the Workshop Manual on MGSS or this SA for Tire, Oil, Battery and Lubricant
Information.
New Rear Transaxle Assembly
A newly developed Rear Transaxle Assembly (A) unit is installed in this model, which
includes a MGR (Motor Generator Rear) to drive the rear wheels and is cooled by air.

Use only genuine ATF WS JWS3324 Automatic Transaxle Fluid, which is same as the Front
Transaxle Fluid (full level is approximately 1.8 quarts (1.7L) as shown.
REAR DRIVE UNIT

B: Filler Plug
D: 0 - 0.2 in (5mm)
E: Injection Nozzle

B: Filler Plug
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C: Drain Plug
This new Rear Transaxle Assy (A) unit needs to be replaced as a complete unit (27-100).
Implement the initialization for the resolver (rotation angle sensor to control the motor) using
M-MDS when replacing the Rear Transaxle Assembly.
CAUTION: DO NOT use a hydraulic jack on this unit - use a jack at the side sills instead.
This new Front Transaxle Assembly unit needs to be replaced as a complete unit (19-090).
Refer to the Workshop Manual on MGSS or this SA for Tire, Oil, Battery and Lubricant
Information.
Closed Fuel Tank
Lower the pressure in the closed fuel tank using the fuel lid opener switch. The lid can be
opened after lowering the pressure (about 10 seconds) before service.
Refer to the Workshop Manual on MGSS for further details.

FUEL-FILLER LID LOCK
ACTUATOR

Electronically Controlled Brake System
The Brake system is an Accumulator-Based Electronically Controlled Brake System (Brake
by Wire) which has complex hydraulic circuit. Because of this complexity, there is potential
the system cannot be emptying air from the hydraulic circuit by pedal-pumping and valve
activation, and a special repair method is required. Refer to the instructions on MGSS when
servicing brake component parts.
CAUTION: Only use the Brake Fluids listed below for Electronically controlled brake unit (A)
equipped on this hybrid model. This is to prevent damage to rubber parts.
B060 DOT3 (CCI): equal to Mazda Genuine Brake Fluid B7
Equivalent Brake Fluids:
• GC325M/GC325 DOT3 (CCI)
• SH-H DOT3 (Fuji Kako)
NOTE: Safe Brake 16M/9M DOT4 (Clariant) cannot be used.
Applying general standards such as FMVSS, DOT3/DOT4 is NOT sufficient to use.
Always make sure to depressurize the brake system (the red pipe (B) has high pressure of
approx.10 Mpa even at IG OFF as shown in the figure) before inspection, service,
or replacement for safety.

BRAKE SYSTEM

A: Booster Pump Assembly
B: High Pressure Pipe Line
C: Electronically Controlled Brake Unit
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Refer to the Workshop Manual on MGSS for detailed procedures.
High Voltage Battery
A Ni-Hydride Battery (A) (Ni-MH Battery Pack: 245 volts, named High Voltage Battery) is
used on this hybrid model and is cooled by air.

HV BATTERY

*1 Battery Cooling Blower Assembly
*2 HV Battery Thermistor
*3 Hybrid Battery Junction Block Assembly
*4 Service Plug Grip
*5 HV Battery Modules
*6 Battery Smart Unit (Battery Voltage Sensor)

HV BATTERY COOLING
SYSTEM

Storage of new High Voltage Battery (Ni-MH)
In addition to the following, verify the laws and ordinances of each country.
Avoid direct sunlight and store High Voltage Battery (Ni-MH) in a dark and dry place at 23 to
86 degrees F (-5 to 30 degrees C).
Air Filter User Maintenance for New Ni-MH Battery
Perform cleaning immediately with a soft brush on a vacuum hose (or tapping on the ground
if vacuum cleaner is not available) when a message is displayed on the multi-information
display. If filter is excessively dirty, replace the filter.
WARNING: DO NOT clean with water or liquids. If the high voltage battery gets wet, it may
cause a malfunction or vehicle fire.
CAUTION:
• If you continue driving while the message is displayed, the high voltage battery may be
damaged.
• DO NOT use an air blower for cleaning. Otherwise, dust could be forced in which
could decrease the high voltage battery output or damage it.

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Rear Seat

B: Air Inlet
C: Air Outlet
*1: Battery Cooling Blower Assembly
*2: Hybrid Battery Module
NOTE: After cleaning, the vehicle may need to be driven for about 20 minutes for the
message displayed on the multi-information display to go away. Refer to the Owner's Manual
and the Workshop Manual on MGSS for more details.
lnner Service of High Voltage Battery (Ni-MH Battery Pack: 245 volts)
NO Modules can be replaced for the Ni-MH Battery Pack. Only some sensors and relays
inside of the Ni-MH Battery Pack can be replaced as shown

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*1 Hybrid Battery Junction Block
*2 SMRB
*3 SMRP
*4 SMRG
*5 Battery Current Sensor
*6 Precharge Resistor
Coolant Drain and Replacement
The PCU (Power Control Unit) and oil (ATF) cooler uses the cooling system (Low
Temperature (LT) line) with an electric water pump. The High Temperature (HT) line is for
cooling the Engine, and uses another electric water pump. Each line has a scheduled
maintenance interval.
NOTE: LT line does not have a drain plug, therefore, always make sure to remove a joint in
the middle of hose to drain the coolant as shown in the figure below. The HT line has a drain
plug at the radiator.
COOLING SYSTEM

A: Joint Low Temperature (LT)
B: Drain Plug High Temperature (HT)

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C: Joint Low Temperature (LT)

D: Water Sensor High Temperature (HT)
E: Power Control Unit (PCU)
Perform the air drainage process according to the Workshop Manual on MGSS after the
coolant (FL22 type) is drained and replaced.
NOTE: There are both methods to operate the electric water pump (with and without Mazda
Modular Diagnostic System (M-MDS)). Refer to the Workshop Manual on MGSS for more
details.
Towing
CAUTION: When towed, all 4 wheels must be off the ground as shown in the figures,
otherwise the MOTOR will generate electricity and may cause system damage.

TOWING
or

Refer to the Owner's Manual and Rescue Manual on MGSS for more details.
No Jump Start Function
CAUTION: DO NOT Jump Start other vehicles with a dead battery because the PCU of this

SERVICE CAUTIONS
WHEN LEAD-ACID
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hybrid model does not have the sufficient specification for it, and may cause a dead 12 volts BATTERY IS
lead-acid battery. This hybrid model can be jump started from other vehicles. In this case, the DISCHARGED
plus clip needs to be installed at the terminal in the main fuse box (engine room) as shown in
the figure because the 12 volts lead-acid battery is located in the trunk.

*a - Booster Terminal
*b - Auxiliary battery of rescue vehicle
1 - Booster terminal of stalled vehicle
2 - Positive (+) auxiliary battery terminal of rescue vehicle
3 - Negative (-) auxiliary battery terminal of rescue vehicle
4 - Position shown in the illustration on stalled vehicle
Main fuse box (engine room)

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12V battery located in the trunk.
Refer to the Owner's Manual for more details.
Tire Changing of Mazda Genuine Aluminum Wheel (with rim steps approx. 2mm)
CAUTION: Always make sure to place the Mount Head (A) of the tire changer at the
higher (convex) (B) rim area as shown in the figure, otherwise the wheel might be damaged
when removing the tire.
DO NOT place the Mount Head at lower (concave) (C) rim area, in which you can easily
place the Mount Head (A).

STEPPED RIM
VERIFICATION AND
CAUTIONARY NOTES

A: Mount Head
B: Convex
C: Concave
Refer to the Workshop Manual on MGSS for further detailed procedures.
Shift Mechanism
Only adjust the shift cable at the Neutral position on this hybrid model, and not at the Park
position like on the non-hybrid CX-50. Insert the cable from the engine room on the hybrid
model, not from the cabin as like on the non-hybrid CX-50.
To unlock the Parking lock, always make sure to open the console and operate the unlock
lever as shown in the figure below for thius hybrid model (dealer service), not by unlock
bottom at the console like the non-hybrid CX-50 (user service).

SELECTOR CABLE
ADJUSTMENT

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Maintenance Notification
The maintenance notification function alerts drivers of maintenance needs by turning on the
wrench indicator light

and displaying a message in the instrument panel. The followings are the normal operation of
notification:
(a) : When the unit of distance setting is selected “mile”
Although a push notification on MyMazda App at 600 miles of remaining distance until
oil change, no message is displayed in the instrument panel due to ECM specification
(THS-II hybrid system). Displaying a message in the instrument panel will be at 500
miles of remaining distance until oil change.
NOTE: When the unit of distance setting is selected “km”, a push notification
(MyMazda App) and message (instrument panel) appear at 1,000km of remaining
INSTRUMENT
distance until oil change.
(b) : The remaining distance until oil change may display “---- mile or km” in the Mazda CLUSTER
Connect (vehicle status monitor screen) and MyMazda AppMCVV if the ECM (THS-II
hybrid system) has not completed the calculation of engine oil deterioration.

(c) : The maximum interval of remaining distance until oil change may display “16,090
km” or “9,999 mi” in the center display after performing engine oil data reset due to
ECM specification (THS-II hybrid system).

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