BULLETIN NOTES
This bulletin supersedes the previously issued bulletin(s) listed below. The changes are noted in Red text.
Previous TSBs:

Date(s) Issued:

01-005/24

06/10/24, 06/27/24, 08/29/24 and 11/04/24

01-005/23

02/16/23 and 12/20/23

01-013/22

10/19/22

01-011/21

09/27/21 and 04/22/21

APPLICABLE MODEL(S)/VINS
2019-2022 CX-3 2.0/2.5L with VINs lower than JM1DK******605934 (produced before July 8, 2022)
2020-2023 CX-30 2.0/2.5L (Mexico built) with VINs lower than 3MVDM******589428 (produced before Sep. 1, 2023)
2018-2025 CX-5 2.0/2.5L with VINs lower than JM3KF******617579 (produced before Dec. 18, 2024)
2019-2023 Mazda3 2.0/2.5L (Japan built) with VINs lower than JM1BP******623951 (produced before May 23, 2023)
2019-2023 Mazda3 2.0/2.5L (Mexico built) with VINs lower than 3MZBP******384076 (produced before Sep. 5, 2023)
2018-2021 Mazda6 2.0/2.5L with VINs lower than JM1GL******620105 (produced before Nov. 12, 2021)
NOTE: Vehicles with SKYACTIV-G 2.5T (turbo) engine are not applicable to this service information.

DESCRIPTION
Some customers may experience a check engine light ON with DTC P0126:00 (Thermostat stuck open) and one or more
of the following symptoms:
•
•
•
•

Engine takes longer to warm up.
Engine temperature gauge fluctuates.
Low coolant temperature indicator (blue) light stays on longer or turns on while driving.
Poor heater performance, especially at idle.

NOTE:
• Vehicles with SKYACTIV-G 2.5T are not applicable to this service information.
• If DTC P2B61:00 (Coolant control valve circuit range/performance) accompanies DTC P0126:00, this TSB is not
applicable. Diagnose DTCs according to the instructions on MGSS online.
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Customers having this concern should have their vehicle repaired using the following repair procedure.

REPAIR PROCEDURE
NOTE: If DTC P2B61:00 (Coolant control valve circuit range/performance) registered, this Service Information is not
applicable. Diagnose according to the instruction on MGSS online.
1. Verify customer concerns and check the coolant temperature in the freeze frame data.
- If it is at around 40-80 °C {104-176 °F} proceed to step 2.
- If it is not at around 40-80 °C {104-176 °F}, this Service Information is not applicable. Diagnose according to the
instruction on MGSS online.
2. Remove the coolant control valve according to the instruction on MGSS:
•
•
•
•
•

Mazda3 (COOLANT CONTROL VALVE REMOVAL/INSTALLATION)
Mazda6 (COOLANT CONTROL VALVE REMOVAL/INSTALLATION)
CX-3 (COOLANT CONTROL VALVE REMOVAL/INSTALLATION)
CX-5 (COOLANT CONTROL VALVE REMOVAL/INSTALLATION)
CX-30 (COOLANT CONTROL VALVE REMOVAL/INSTALLATION)

3. Remove thermostat cover and thermostat cover gasket from coolant control valve.

1. Thermostat
2. Thermostat cover gasket
3. Thermostat cover
4. Water outlet gasket

a. Mark the four (4) screws and the respective holes before loosening them to ensure that the screws are placed in their
original holes when reinstalling.
NOTE: If the screws are not reinstalled in their original holes, the holes may become deformed.

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Marking Example 1: Draw lines over the
screws and the thermostat cover as shown
above.

Marking Example 2: Number each screw and their
respective hole as shown above.

b. Loosen the four (4) tapping screws fastening the thermostat cover.
CAUTION: Use hand tools only, do not use power tools.

4. Replace the thermostat with a new one included in the thermostat set.
NOTE: Do not use lubricants, spray lube, silicone sealer or petroleum grease on any of the gaskets.

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Thermostat set includes:
1. Thermostat cover gasket*
2. Thermostat cover
3. Water outlet gasket
4. Thermostat
*Thermostat cover gasket is already assembled to the ther
mostat cover.
a. Before installing the thermostat, check the mounting area for dirt and clean the area.

b. When installing the thermostat, push it firmly until it makes a clicking noise to ensure it has been installed properly.
NOTE:
• Insert the thermostat so that its notch matches the protuding area in the hole.
• Add 1-2 drops of coolant as necessary to the O-ring to help slide it into the thermostat housing.

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5. Install the new thermostat cover and the thermostat cover gasket (included in the thermostat set) to the coolant control
valve body.

a. Ensure that the thermostat cover gasket is inserted correctly in thermostat cover slot.

b. Place each of the marked four (4) screws in their respective holes and tighten them by hand. If resistance is felt,
unscrew once, and repeat the procedure.
NOTE:
• If screws are not inserted in their original holes, holes may become deformed.
• Do not use lubricants, spray lube, silicone sealer or petroleum grease on any of the gaskets.
c. Tighten the screws in a criss-cross pattern.
Tightening torque: Tighten screws to 26 in. lbs (3 Nm), then repeat tightening to 44 in. lbs (5 Nm).
CAUTION: Use hand tools only, do not use power tools.

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6. Reinstall the coolant control valve and the new water outlet gasket (included in the thermostat set) to the
vehicle according to the instruction on MGSS.
7. Verify the repair by inspecting for engine coolant leakage.
NOTE: If the subject vehicle comes back again with DTC P0126:00, perform this TSB again. There is no need to contact
the technical hotline for warranty approval.

PARTS INFORMATION
Parts Number
PYY2-15-SA1
PYFB-15-169
PE13-15-296
0000-77-508F-20
[R]: Replacement parts

Description
THERMOSTAT SET
GASKET,WATER OUTLET
CONNECTOR
COOLANT

Qty.
1
1
1
2

Notes
--[R] for Lower radiator hose component
[R] for water hose for A/T oil cooler
7.4 L {7.8 US qt, 6.5 Imp qt} maximum

WARRANTY INFORMATION
NOTE:
• This warranty information applies only to verified customer complaints on vehicles eligible for warranty repair.
• Additional diagnostic time cannot be claimed for this repair.
• This repair will be covered under Mazda’s Powertrain Warranty:
Calif. Emission Warranty:
U.S.A. except 2018 MAZDA6, 2019/2020/2022 CX-3 and 2018 CX-5:
Calif. Emission Warranty (long term)
U.S.A. 2018 MAZDA6, 2019/2020 CX-3 and 2018 CX-5:
Calif. Emission Warranty (short term)

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Warranty Type Code
Symptom Code
Damage Code
Causal Part No.
Quantity
Operation No. and Labor H
ours

Model
Mazda3

A
6X
9K
PYY2-15-SA1
1
Refer to the table below

Engine
PE
PY

Variation

Operation No

Labor Hours (hrs.)

---

XXWPDARX

1.5

CX-30

PE / PY

---

XXWPDARX

1.5

CX-3

PE

---

XXWPDARX

1.5

PE

MT
AT

XXWPDARX

1.5

PY

AT

XXWPDCRX

1.6

XXWPDCRX

1.6

CX-5

PE
Mazda6

PY

---

NOTE:
• If the subject vehicle comes back again with DTC P0126:00, perform this TSB again. There is no need to contact
the technical hotline for warranty approval.
• For repairs of out of warranty period, refer to SSPD8 (except for Mexico).

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