P0384 Glow Plug/Heater Circuit B High

P0384 indicates a high condition in Glow Plug or Heater Circuit B. The circuit feedback or voltage is above the range expected during glow/heater operation.

Code details

Generic OBD-II · P0
System
Ignition / Misfire
Code type
Generic (SAE / ISO controlled)
Standard
SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not keep cycling the glow system with a suspected stuck-high heater circuit until wiring and relay behavior are confirmed.

Symptoms of P0384

Common causes of P0384

Useful checks before replacing parts

Related OBD-II codes

These nearby ignition / misfire entries can help compare wording and pin down the fault area.