OBD Guide
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P0621

Generator Lamp/L Terminal Circuit

P0621 is an OBD-II diagnostic trouble code meaning: Generator Lamp/L Terminal Circuit. Common causes: burnt out or broken control lamp in terminal l circuit, broken wire terminal l between the generator and the instrument panel/ecu. Estimated repair cost: $6–278.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$6–278 (est.)

Symptoms

  • The battery light comes on or flashes
  • The Check Engine light comes on
  • Unstable charging voltage
  • Sometimes - normal charging operation if there is a code
  • Possible incorrect behavior of the charging control system

Causes

  • Burnt out or broken control lamp in terminal L circuit
  • Broken wire terminal L between the generator and the instrument panel/ECU
  • Short circuit of terminal L wire to ground
  • Malfunction of the voltage regulator with terminal L
  • Oxidation of the generator connector

How to Fix

  1. Check the status of the battery warning lamp on the dashboard
  2. Measure the voltage at terminal L of the generator with the engine running.
  3. Check wiring from terminal L to instrument panel and ECU
  4. Check the generator connector - clean it from oxidation
  5. Check generator voltage regulator
  6. If the external circuit is working, diagnostics/replacement of the generator

Related codes

P0620P0622P0623P0562P0563

Error P0621 by Vehicle Brand

AcuraAudiBAICBMWBYDBuickCadillacChanganCheryChevroletChryslerCitroenDodgeDongfengExeedFAWFordForthingFotonGACGMGMCGeelyGreat WallHavalHondaHongqiHyundaiInfinitiJACJaecooJaguarJeepJetourKaiyiKiaLadaLexusLi AutoLifanLincolnLivanMazdaMercedes-BenzMercuryMitsubishiNIONissanOldsmobileOmodaOpelPeugeotPlymouthPontiacRenaultSWMSaturnSkodaSkywellSubaruSuzukiTankToyotaVolkswagenVolvoVoyahXPengZeekrZotye

FAQ

What does the P0621 code mean?

P0621 is an OBD-II diagnostic trouble code that indicates: Generator Lamp/L Terminal Circuit

What causes a P0621 error code?

The most common causes of P0621 include: Burnt out or broken control lamp in terminal L circuit; Broken wire terminal L between the generator and the instrument panel/ECU; Short circuit of terminal L wire to ground; Malfunction of the voltage regulator with terminal L.

How do I fix a P0621 diagnostic trouble code?

To fix P0621: Check the status of the battery warning lamp on the dashboard. Measure the voltage at terminal L of the generator with the engine running.. Check wiring from terminal L to instrument panel and ECU. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P0621?

Limited driving only, diagnose soon

How much does it cost to fix P0621?

The estimated repair cost for P0621 is $6–278. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat