Inspect safely
DENSO advises visual inspection, performance testing and a fully charged battery before electrical-system diagnosis. A swollen, leaking or physically damaged battery needs safe handling, not another charging attempt. Follow battery and vehicle precautions.
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Test under the right conditions
A voltage reading is one observation. Temperature, state of charge and loaded performance affect interpretation. Use equipment appropriate to the battery type and its rated specification, and include the connections and grounds in the assessment.
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Keep the results
Ask for the measured test result and the battery’s identification. Record recent charging, jump-starts and storage history. Establishing battery condition first prevents a low supply voltage from being mistaken for a failed starter, alternator or unrelated electronic module.
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- Component manufacturer technical guidance ↗Reviewed Oct 6, 2026
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