Powertrain, generic · Ignition system or misfire

P0380 Glow Plug/Heater Circuit A

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P0380 concerns glow plug circuit A – depending on the manufacturer the first group of plugs, glow relay 1 or feedback line A of the glow plug control module. Saab's 3.0 TiD (9-5, 2002) has two feedback lines from the control module; if line A at the engine module stays above 4.0 V for more than 3 s while glowing, the module is reporting a plug or circuit fault, checked once per drive cycle with the warning lamp on. In Saab's 1.9 TiD (EDC16) the glow plug control module drives two pairs of plugs, monitors them itself and reports faults over a diagnostic line that should switch inversely to the activation line. The 2010/11 Saab 9-5 2.0 TiD sets P0380 for implausible feedback or a missing supply of the module, there without check engine light. Newer GM and Ford diesels report single plugs under P0671 ff instead.

Likely causes

Glow plug(s) in circuit A burnt out
Glow plug control module or glow relay faulty
Wiring or connector fault (feedback line, plug connector, supply)
Missing battery or ignition supply of the control module (fuse)

Symptoms

  • Hard starting when cold, long cranking
  • White or blue smoke and rough running after a cold start
  • Glow plug light or check engine light on or flashing

Repair estimate

DifficultyMediumDIY possible
Parts and labour€80–600
Time0.5–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

What to check first

  1. Measure resistance of each glow plug
  2. Check control module and fuse
  3. Inspect wiring

Parts involved

glow plugglow plug control moduleglow plug relayglow plug wiring

Related codes

P0382P0670P0671P0683P0381

References: saabwisonline.com, saabwisonline.com, saabwisonline.com, saabwisonline.com.