Glow Plug/Heater Circuit B
The P0382 code means the vehicle's onboard diagnostic system has detected: Glow Plug/Heater Circuit B. This is a moderate severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- moderate
- Estimated cost
- $100 - $500 (parts and labor)
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Common Symptoms
- Check Engine Light on
- Difficult cold starting
- White smoke on cold start
- Rough idle when cold
Probable Causes (Ranked by Likelihood)
- Faulty glow plugs on circuit B (Bank 2) Very High
- Faulty glow plug relay B or control module B High
- Wiring damage on Bank 2 glow plug circuit Moderate
- PCM/module communication fault Low
Frequently Asked Questions
What is glow plug circuit B?
Circuit B typically refers to the glow plugs on Bank 2 of a V-configuration diesel engine. V8 diesels have 4 glow plugs per bank.
Is P0382 different from P0380?
P0380 is Circuit A (Bank 1 or all plugs), while P0382 is Circuit B (Bank 2 on V-engines). The diagnostic approach is the same.
Can I replace just the bad glow plug?
Yes, but glow plugs are inexpensive ($10-$30 each), so replacing all plugs on the affected bank is recommended.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
-
Test Bank 2 glow plugs individually with clamp ammeter.
-
Measure each glow plug resistance on Bank 2.
-
Check Bank 2 glow plug relay/module.
-
Inspect Bank 2 wiring for damage.
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
Commonly Affected Vehicles
- 2010-2020 Ford F-350 (6.7L Diesel)
- 2012-2019 Chevrolet Silverado 3500 (6.6L Duramax)
- 2008-2018 Ram 3500 (6.7L Cummins)
- 2011-2020 GMC Sierra 3500 (6.6L Duramax)
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