Powertrain, generic · Ignition system or misfire

P0382 Glow Plug/Heater Circuit B

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P0382 is the counterpart of P0380 for glow plug circuit B – depending on the manufacturer the second group of plugs, glow relay 2 or feedback line B of the glow plug control module. A code-specific manufacturer description exists from Saab: the 3.0 TiD V6 diesel in the 9-5 (2002) reads two feedback lines from its glow plug control module, and if line B stays above 4.0 V for more than 3 s while glowing, the module is reporting a fault in the second group of plugs; the check runs once per drive cycle, the warning lamp comes on and there is no further system reaction. Newer GM and Ford diesels report single plugs under P0671 ff and do not use P0382. CARB requires glow plug circuits to be monitored for correct current and voltage drop. The typical consequence is a poor cold start with smoke.

Likely causes

Glow plug(s) in circuit B burnt out
Glow plug control module or glow relay 2 faulty
Feedback line B, plug connector or busbar faulty

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.

Parts involved

glow plugglow plug control moduleglow plug relayglow plug wiring

Related codes

P0380P0670P0671P0683

References: saabwisonline.com, saabwisonline.com, law.cornell.edu.