Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2021 Mazda 3 BaseFACTORY OEM SERVICE PROCEDURE
Shift-Lock System Inspection
- Switch the ignition ON (engine off).
- Shift the selector lever to the P position.
- Verify that push button cannot be pressed in and the selector lever cannot be shifted from the P to R position when the brake pedal is not depressed.
- If it can be verified, go to the next step.
- If not as verified, inspect the following parts:
- Shift-lock solenoid (See SHIFT-LOCK SOLENOID INSPECTION .)
- Not P position switch (See NOT P POSITION SWITCH INSPECTION .)
- Indicator (See INDICATOR INSPECTION .)
- Brake switch (See BRAKE SWITCH INSPECTION .)
- Body control module (BCM) (See BODY CONTROL MODULE (BCM) INSPECTION (US) .)
- Electrical supply unit (ESU) (See ELECTRICAL SUPPLY UNIT (ESU) INSPECTION .)
- PCM (See PCM INSPECTION [(VIN 7 & VIN L) (US)] .) (See PCM INSPECTION [(VIN M) (US)] .) (See PCM INSPECTION [(VIN Y) (US)] .)
- Verify that the selector lever can be shifted from P to R position while the push button is pressed with brake pedal depressed.
- If not as verified, inspect the following parts:
- Shift-lock solenoid (See SHIFT-LOCK SOLENOID INSPECTION .)
- Not P position switch (See NOT P POSITION SWITCH INSPECTION .)
- Indicator (See INDICATOR INSPECTION .)
- Brake switch (See BRAKE SWITCH INSPECTION .)
- Body control module (BCM) (See BODY CONTROL MODULE (BCM) INSPECTION (US) .)
- Electrical supply unit (ESU) (See ELECTRICAL SUPPLY UNIT (ESU) INSPECTION .)
- PCM (See PCM INSPECTION [(VIN 7 & VIN L) (US)] .) (See PCM INSPECTION [(VIN M) (US)] .) (See PCM INSPECTION [(VIN Y) (US)] .)
- If not as verified, inspect the following parts:
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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