P0382
Fix within a few daysYour diesel engine's computer detected a problem with the glow plug circuit 'B'. This means one or more glow plugs, or their control system, is not working correctly.
Code P0382 means there's a problem with your diesel engine's glow plug circuit 'B'. Common causes: Faulty glow plug (70%), glow plug control module (20%). Drivability: Yes, but expect hard starts in cold weather. Repair cost: $20-$200 DIY, $150-$700 professional.
Can I Drive With P0382?
Yes, for short trips only
Essential trips under 10 miles, avoid highways if the engine is running very rough. Prioritize repair before cold weather.
Stop driving immediately if: Engine will not start at all, or runs extremely rough with severe misfires.
Symptoms of P0382
- 1Engine is hard to start, especially in cold weather
- 2Engine misfires or runs rough immediately after starting
- 3White smoke from the exhaust on startup
- 4Check Engine Light is on
Common Causes of P0382
Parts most likely causing this code, ranked by probability
A failed glow plug in the affected circuit prevents proper heating of the combustion chamber, leading to hard starts.
70% of P0382 cases are fixed by replacing a faulty glow plug
A malfunctioning control module or relay fails to send power to the glow plugs, preventing them from heating.
20% of P0382 cases are fixed by replacing the glow plug control module
Corroded, damaged, or loose wiring and connectors interrupt the electrical signal to the glow plugs or control module.
8% of P0382 cases are fixed by repairing wiring or connectors
A rare internal fault within the engine's computer can incorrectly command or monitor the glow plug circuit.
2% of P0382 cases are fixed by replacing the ECM/PCM
Check These First (Before Buying Parts)
- Check for any other glow plug related codes (P0380, P0381, P0383, P0384).
- Visually inspect the glow plugs and their wiring for any obvious damage, corrosion, or loose connections.
How to Diagnose P0382
- 1Check for other glow plug related codes (P0380, P0381, P0383, P0384) to pinpoint the exact issue.
- 2Visually inspect the glow plugs, their wiring, and connectors for any signs of damage, corrosion, or looseness.
- 3Use a multimeter to test the resistance of the glow plugs in circuit 'B'; a high or infinite resistance indicates a bad glow plug.
- 4Check for voltage at the glow plug connectors during cold start to confirm the control module is sending power.
- 5If glow plugs and wiring are good, test the glow plug control module/relay for proper operation and power supply.
P0382 on Popular Vehicles
Ford F-250/F-350 (Powerstroke)
2003-2024Glow plug failures are common. The Glow Plug Control Module (GPCM) is also a frequent culprit. Access to glow plugs can be difficult, especially on the passenger side, requiring removal of the inner fender or other components.
75% fixed by replacing glow plugs or GPCM
Chevrolet Silverado/GMC Sierra (Duramax)
2001-2024Glow plug failures are common, and the glow plug controller (module) can also fail. Diagnosing individual glow plugs with a multimeter is a key step. Access can be tight but is generally manageable.
70% fixed by replacing glow plugs or control module
Ram 2500/3500 (Cummins)
2003-2024Cummins engines are known for glow plug issues, particularly with age. The glow plug relay/controller is another common failure point. Always check wiring for corrosion, especially in areas exposed to road salt.
70% fixed by replacing glow plugs or relay
Frequently Asked Questions
What does P0382 mean?
P0382 indicates that your vehicle's engine control module (ECM) has detected a malfunction in the glow plug/heater circuit 'B'. This circuit is essential for heating the combustion chambers in a diesel engine, especially during cold starts.
Can I drive with P0382?
Yes, you can drive with P0382, but expect hard starting, especially in cold weather. The engine will likely run rough for a short period after starting. Prolonged driving with this issue can strain your battery and starter.
Will P0382 clear itself?
No, P0382 will not clear itself. The underlying electrical or component fault must be diagnosed and repaired. Once the repair is complete, you can clear the code with an OBD-II scanner, or it will clear after several drive cycles if the fault is resolved.
How do I fix P0382 myself?
Start by visually inspecting the glow plugs and their wiring. Use a multimeter to test the resistance of each glow plug in the affected circuit. If a glow plug shows high resistance, replace it. If the glow plugs are good, test the glow plug control module for proper operation and power supply.
How much does it cost to fix P0382?
The cost to fix P0382 yourself ranges from $20 to $200, depending on whether you replace a single glow plug or a full set. Professional repair costs range from $150 to $700, including parts and labor, as glow plugs can be difficult to access on some engines.
P0382 keeps coming back - why?
If P0382 keeps returning, it indicates the root cause was not fully addressed. This often happens if only one glow plug was replaced when others were also weak, or if the glow plug control module or wiring issue was overlooked during the initial repair.
Will P0382 fail emissions/smog test?
Yes, P0382 will cause your vehicle to fail an emissions or smog test. A malfunctioning glow plug system directly impacts cold start emissions and indicates a fault in a critical engine system, which will prevent the vehicle from passing inspection.
What's the difference between P0382 and P0380?
P0380 indicates a general malfunction in the glow plug/heater circuit, meaning there's an issue with the overall system. P0382 is more specific, pointing to a malfunction in 'Circuit B', which often refers to a specific bank of cylinders or a particular part of the glow plug system.
P0382 on Ford F-250/F-350 (Powerstroke)
On Ford Powerstroke engines, P0382 commonly points to a failed glow plug or a faulty glow plug control module (GPCM). Accessing the glow plugs can be challenging, especially on the passenger side, requiring removal of other components. The GPCM is a frequent failure point on these trucks.
Questions to Ask Your Mechanic
Did you test the resistance of each glow plug in circuit 'B' individually?
Good answer: Yes, I tested each glow plug with a multimeter. Cylinder X's glow plug showed infinite resistance, indicating it's open, or cylinder Y's glow plug showed very high resistance.
What voltage did you measure at the glow plug connectors during a cold start cycle?
Good answer: I measured battery voltage (around 12V) at the glow plug connectors for the first 10-15 seconds during a cold start, confirming the control module is sending power. The issue is with the glow plug itself.
Repair Cost Estimate
DIY Repair
Parts only
$20-$200
Shop Repair
Parts + labor
$150-$700
Save $130-$500 by doing it yourself
Difficulty
intermediate
Time
1-3 hours
Intermediate - requires a multimeter for testing and specific glow plug sockets. Access can be challenging on some engines.
Cost of Waiting
Ignoring P0382 leads to hard starting, especially in cold weather. This significantly strains your battery and starter, potentially causing premature failure of these expensive components. A $50 glow plug fix now prevents a $300 battery or $500 starter replacement later.
While You're In There...
Glow plugs often wear out at similar rates. If one has failed, others are likely to follow soon. Replacing them all at once saves on future labor costs.
If you're already diagnosing the glow plug circuit, testing or replacing the control module is a logical next step, as it's a common failure point and directly related to the code.
Tools You'll Need
- OBD-II Scanner
- Multimeter
- Glow plug socket set
- Torque wrench
- Basic hand tools (ratchets, extensions, wrenches)
P0382 is a common issue for diesel engines, especially as they age. Most repairs are straightforward, and your engine will start reliably again afterward.
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Your Next Steps
Step 1: Use a multimeter to test the resistance of each glow plug in circuit 'B'. A good glow plug will have very low resistance (typically 0.5-2.0 ohms).
Step 2: If a glow plug is faulty, replace it. If all glow plugs test good, proceed to test the glow plug control module/relay and its wiring for proper voltage and continuity.
Step 3: Parts you'll likely need: one or more glow plugs (consider a full set), or a glow plug control module/relay.