What this code means

The PCM has detected that the charging system voltage is above the acceptable range. The voltage regulator in the alternator is allowing excessive voltage, which can damage electrical components and boil battery electrolyte.

Symptoms

• Check Engine Light
• Battery warning light may illuminate
• Electrical components failing prematurely
• Battery swelling or leaking
• Headlights excessively bright

Common causes

• Faulty voltage regulator in alternator
• Poor ground connection at alternator
• Corroded battery cables
• Faulty PCM voltage sense circuit
• Wiring issue in charging circuit

Diagnostic steps

1. Measure charging voltage at battery with engine running (should be 13.5-14.8V)
2. Check alternator ground connection
3. Inspect battery cables and terminals for corrosion
4. Test voltage regulator function
5. Check PCM voltage sense wire

Repair notes

Replace the alternator if the voltage regulator is causing overcharging.

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