OBD Guide
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P0620

Generator Control Circuit

P0620 is an OBD-II diagnostic trouble code meaning: Generator Control Circuit. Common causes: open or short circuit in the generator control circuit (l-wire/d+), faulty generator voltage regulator. Estimated repair cost: $11–278.

Severity
🔴 High
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$11–278 (est.)

Symptoms

  • The Check Engine light comes on
  • The battery indicator on the dashboard is on
  • Unstable on-board voltage
  • Accelerated battery drain
  • Lighting flickering when load changes

Causes

  • Open or short circuit in the generator control circuit (L-wire/D+)
  • Faulty generator voltage regulator
  • Alternator brush malfunction
  • Open circuit in the generator excitation circuit
  • ECU malfunction (generator control channel)

How to Fix

  1. Measure the voltage of the on-board network with the engine running (normal 13.8–14.4 V)
  2. Check the generator control wire between the ECU and the L/D+ terminal
  3. Check generator output voltage and current under load
  4. Check the brushes and slip rings of the generator
  5. Check the voltage regulator - replace if necessary
  6. If the wiring and generator are working properly - ECU diagnostics

Related codes

P0621P0622P0623P0562P0563

Error P0620 by Vehicle Brand

AcuraAudiBAICBMWBYDBuickCadillacChanganCheryChevroletChryslerCitroenDodgeDongfengExeedFAWFordForthingFotonGACGMGMCGeelyGreat WallHavalHondaHongqiHyundaiInfinitiJACJaecooJaguarJeepJetourKaiyiKiaLadaLexusLi AutoLifanLincolnLivanMazdaMercedes-BenzMercuryMitsubishiNIONissanOldsmobileOmodaOpelPeugeotPlymouthPontiacRenaultSWMSaturnSkodaSkywellSubaruSuzukiTankToyotaVolkswagenVolvoVoyahXPengZeekrZotye

FAQ

What does the P0620 code mean?

P0620 is an OBD-II diagnostic trouble code that indicates: Generator Control Circuit

What causes a P0620 error code?

The most common causes of P0620 include: Open or short circuit in the generator control circuit (L-wire/D+); Faulty generator voltage regulator; Alternator brush malfunction; Open circuit in the generator excitation circuit.

How do I fix a P0620 diagnostic trouble code?

To fix P0620: Measure the voltage of the on-board network with the engine running (normal 13.8–14.4 V). Check the generator control wire between the ECU and the L/D+ terminal. Check generator output voltage and current under load. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P0620?

Limited driving only, diagnose soon

How much does it cost to fix P0620?

The estimated repair cost for P0620 is $11–278. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat