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2017 Mazda3 · US · Keys and lights

Replace the Mazda transmitter battery

For the auxiliary-key transmitter with a separate battery cap and rubber ring.

A CR2025 coin cell has a prominent plus sign facing up. A separate rubber ring is highlighted as a part that must remain intact and be refitted if detached. The graphic is not an opening-tool placement guide.
Original schematic. Mazda specifies CR2025 or equivalent, positive pole up, and an intact correctly placed rubber ring. Manual reference

1 Confirm your vehicle

For 2017 Mazda3 · US, SKYACTIV-G 2.0 / 2.5 gasoline. Confirm the original component against the cited manual.

Select and confirm your vehicle before starting.

Help identify your model and equipment
What is excluded?
  • Other model years and markets; imported Axela or diesel models; modified or aftermarket components with a different procedure.

2 Prepare

You can save preparation while your vehicle or equipment is still unconfirmed.

YOUR OBSERVATIONS

Keep the before and after.

Only on this device

Record polarity, rubber-ring seating and the actual response from the reassembled transmitter.

Does a repeat parked check still respond while the cover, cap and auxiliary key remain secure?

3 Follow the steps

Confirm compatibility and choose the readiness branch before recording steps.

  1. Manual reference · PDF page 451
  2. Manual reference · PDF page 451
  3. Manual reference · PDF page 452
  4. Manual reference · PDF page 452 Manual reference · PDF page 450
  5. Manual reference · PDF page 450
  6. Manual reference · PDF page 451
  7. Manual reference · PDF page 451

4 Check the result

  • How did the closed transmitter respond?
  • Battery cap, ring and cover secure; button response restored
  • Record only the result you actually observed. A saved web checklist is not confirmation that a vehicle has been repaired.
  • Is response repeatable with positive-up battery, ring and cover correctly seated?
  • Does a repeat parked check still respond while the cover, cap and auxiliary key remain secure?

Select what you actually observed. If you have only prepared the plan, record that instead.

Stop and get help if

  • Different / damaged transmitter, corroded contacts or a damaged rubber ring
  • No response, case / ring damage or uncertain contacts: arrange transmitter service.
  • A part, label, connector or fastener differs from the cited manual; access requires raising the vehicle; you cannot identify the correct component.

Source & applicability

Original, AI-assisted plan based on owner-manual facts. No physical repair test or manufacturer endorsement is claimed. Content version 2.0.0.

All observation paths

Does the original key match the auxiliary-key, battery-cap design on manual pages 6-38–6-39?

  • Yes — ready for this check: Continue with the steps, stopping if the real component differs from the manual.
  • Not yet / not sure: Preparation saved. Return when the condition is confirmed; leave the vehicle untouched.
  • Different / damaged transmitter, corroded contacts or a damaged rubber ring: No response, case / ring damage or uncertain contacts: arrange transmitter service.

How did the closed transmitter respond?

  • Battery cap, ring and cover secure; button response restored: Is response repeatable with positive-up battery, ring and cover correctly seated?
  • No response, case / ring damage or uncertain contacts: arrange transmitter service.: No response, case / ring damage or uncertain contacts: arrange transmitter service.
  • I have only prepared the plan: Plan prepared; no physical maintenance result recorded.

Is response repeatable with positive-up battery, ring and cover correctly seated?

  • Response repeatable; ring and closure secure: Battery cap, ring and cover secure; button response restored
  • The observation or repeat check is still incomplete: Plan prepared; no physical maintenance result recorded.
  • Unreliable response, ring damage or loose closure: No response, case / ring damage or uncertain contacts: arrange transmitter service.

All observation paths

Does the original key match the auxiliary-key, battery-cap design on manual pages 6-38–6-39?

  • Yes — ready for this check: Continue with the steps, stopping if the real component differs from the manual.
  • Not yet / not sure: Preparation saved. Return when the condition is confirmed; leave the vehicle untouched.
  • Different / damaged transmitter, corroded contacts or a damaged rubber ring: No response, case / ring damage or uncertain contacts: arrange transmitter service.

How did the closed transmitter respond?

  • Battery cap, ring and cover secure; button response restored: Is response repeatable with positive-up battery, ring and cover correctly seated?
  • No response, case / ring damage or uncertain contacts: arrange transmitter service.: No response, case / ring damage or uncertain contacts: arrange transmitter service.
  • I have only prepared the plan: Plan prepared; no physical maintenance result recorded.

Is response repeatable with positive-up battery, ring and cover correctly seated?

  • Response repeatable; ring and closure secure: Battery cap, ring and cover secure; button response restored
  • The observation or repeat check is still incomplete: Plan prepared; no physical maintenance result recorded.
  • Unreliable response, ring damage or loose closure: No response, case / ring damage or uncertain contacts: arrange transmitter service.

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