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.
2003 Mazda MPV ESFACTORY OEM SERVICE PROCEDURE
Main Relay
NOTE:
On MAZDA6, when testing ET control relay, use main relay testing procedure.
- Ensure main relay clicks when ignition is turned on and off. If no sound is heard, locate and remove main relay from main fuse box, in engine compartment. Using ohmmeter, check continuity between main relay terminals "C" and "D". See Fig 1 and Fig 2 . Continuity should not be present.
- Using fused jumper wires, apply battery voltage to main relay terminal "A" and ground terminal "B" (terminal E" on MAZDA6 & MPV). Continuity should be present between main relay terminals "C" and "D". See Fig 1 and Fig 2 . If continuity is not as specified, replace main relay.
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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