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P1391
Sistema
Powertrain (Diesel)
Scanner richiesto
Enhanced OBD2 scanner (live data graphs, freeze frame, battery voltage test)

Glow Plug Circuit Low (Cylinder 1) — Diesel

Understand P1391, common causes, and the right TOPDON scanner to diagnose it.

Glow plug circuit low on cylinder 1 — diesel cold-start aid.

Sintomi comuni

  • Hard cold start
  • White smoke on cold start
  • Check engine light

Cause tipiche

  • Failed glow plug
  • Short in glow plug circuit
  • Glow plug module fault

Di quale scanner hai bisogno?

Enhanced OBD2 scanner (live data graphs, freeze frame, battery voltage test)

Usa dati live e freeze frame prima di sostituire componenti. I codici ABS, SRS e U richiedono di solito uno scanner full-system.

Consigli diagnostici

  • Registra il freeze frame quando compare il codice
  • Cancella il codice solo dopo aver risolto la causa
  • Controlla codici pending correlati
  • Verifica che la batteria sia sopra 12,4 V prima di sospettare i sensori

Scanner TOPDON consigliati

Domande frequenti

What does P1391 mean?
P1391 indicates glow plug circuit low (cylinder 1) — diesel. Glow plug circuit low on cylinder 1 — diesel cold-start aid.
Can I diagnose P1391 with a basic code reader?
P1391 may set in the engine module, but related diagnostics often benefit from an enhanced or full-system scanner with live data and freeze frame.
Which TOPDON scanner do I need for P1391?
Enhanced OBD2 scanner (live data graphs, freeze frame, battery voltage test) See recommended tools on this page.
Is it safe to drive with P1391?
It depends on the code and symptoms. Flashing check engine lights and misfire codes should be addressed immediately. Consult a professional if unsure.