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.

2006 Mazda 6 MazdaspeedFACTORY OEM SERVICE PROCEDURE

DTC P2504: Notes

DTC P2504 DETECTION CONDITION AND POSSIBLE CAUSES

DTC P2504

Charging system voltage high

DETECTION CONDITION

PCM determines that the generator output voltage is above 18.5 V or the battery voltage is above 16.0 V while the engine is running.

Diagnostic support note

This is a continuous monitor (Other).
The MIL does not illuminate.
FREEZE FRAME DATA is not available.
DTCs are stored in the PCM memory.

POSSIBLE CAUSE

Short to the power circuit between generator connector terminal D and PCM connector terminal 1 AD
Generator malfunction
PCM and/or generator are poorly connected

Courtesy of MAZDA MOTORS CORP.

Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.

Shop Manual-Ready Tools Compare Repair Quote Quote Shield Pro

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.