Error code

OBD2 P0620

OBD2P0620
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.

What it means

Generator Control Circuit.

Severity

highCan drive, but may experience significant issues like power loss or engine stalling.

Summary

P0620 indicates a malfunction in the alternator's control circuit, which can affect its operation and power output. This issue typically involves wiring or components related to the alternator and battery.

Symptoms

  • Illuminated warning light
  • Stored trouble code P0620
  • Abnormal system voltages (high or low)
  • Battery damage
  • Hard start conditions
  • Engine idle roughness or fluctuation
  • Transmission issues like harsh shifts
  • Power loss in the vehicle

Common Causes

  • Defective alternator
  • Faulty alternator control module
  • Damaged wiring and connectors
  • Voltage spikes from improper jump starting
  • Battery defects causing voltage irregularities

Diagnosis

  1. Record all fault codes and freeze frame data.
  2. Check battery state of charge and serviceability.
  3. Disconnect the battery with a memory saving device to prevent control module damage.
  4. Inspect wiring for damage, corrosion, or shorts.
  5. Test alternator and control module functionality.

Fixes

  • Replace defective alternator
  • Repair damaged wiring and connectors

FAQ

Can I drive with P0620?

You can drive, but it's risky due to potential power loss or engine stalling.

What causes voltage spikes in the system?

Voltage spikes often result from improper jump starting procedures that damage control modules and wiring.

View source

Not affiliated with OBD2. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.

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