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.
Medium severity. Can I keep driving?You can keep driving if the engine starts well, but expect hard cold starts and possibly more smoke. Fix it soon, especially before a winter trip, so you are not left unable to start the car.
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
Most 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)
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It affects emissions.
What each character of P0380 means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- 3: Ignition and misfires
- 80: Specific fault in that system
Frequently asked questions
Can I keep driving with code P0380?
You can keep driving if the engine starts well, but expect hard cold starts and possibly more smoke. Fix it soon, especially before a winter trip, so you are not left unable to start the car.
What causes code P0380?
The most common causes are: 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).
Related codes
- P0382Glow Plug/Heater Circuit B
- P0670Glow Plug Control Module 1 Control Circuit/Open
- P0671Cylinder 1 Glow Plug Circuit/Open
- P0683Glow Plug Control Module 1 to PCM Communication Circuit
- P0381Glow Plug/Heater Indicator Control Circuit/Open
Sources
- saabwisonline.com: p0380
- saabwisonline.com: glow plug control module
- saabwisonline.com: p0380 0f
- saabwisonline.com: control module glow plug 596
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.