Can I drive with code P0380?

✅ Yes — diagnose at your convenience

How much does it cost to fix code P0380?

Repair costs typically range from $50 to $500 depending on the root cause, vehicle make/model, and whether you use a dealer or independent shop.

OBD2 Code P0380: Glow Plug/Heater Circuit

Reviewed by ASE Certified Mechanics · Last updated July 20, 2026

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Quick Answer

P0380 = Glow Plug/Heater Circuit
Severity: Check Soon · System: Powertrain · ✅ Can continue with caution

The P0380 code means Glow Plug/Heater Circuit. Estimated repair cost: $50 – $500.

✅ OK TO DRIVE (short term). Have it diagnosed at your next convenience. Monitor for new symptoms.

📋 Diagnostic Reference

OBD2 Code	`P0380`
Category	Powertrain
Severity	Check Soon
Repair Cost	$50 – $500
Can You Drive?	✅ Yes — diagnose at your convenience

🔍 Symptoms

Check Engine Light on
hard starting in cold weather
excessive white smoke on cold start
glow plug warning light on
engine misfire until warm

⚠️ Most Likely Causes (in order of probability)

Failed glow plug (one or more cylinders)
glow plug relay or module failure
wiring harness damage or corrosion at glow plug connectors
blown glow plug fuse
corroded glow plug bus bar connection

🛠️ Diagnostic Procedure

Step 1: Check glow plug fuse and relay first — most common and cheapest fix

Check glow plug fuse and relay first — most common and cheapest fix

Step 2: Measure resistance at each glow plug terminal to ground — should be 0.5-2.0 ohms

Measure resistance at each glow plug terminal to ground — should be 0.5-2.0 ohms

Step 3: If any glow plug shows infinite resistance: it is burned out — replace all as a ...

If any glow plug shows infinite resistance: it is burned out — replace all as a set

Step 4: Check for battery voltage at glow plug bus bar with key on (glow cycle)

Check for battery voltage at glow plug bus bar with key on (glow cycle)

Step 5: Inspect glow plug connectors for corrosion — clean or replace as needed

Inspect glow plug connectors for corrosion — clean or replace as needed

Step 6: Test glow plug relay operation with a multimeter or scan tool activation test.

Test glow plug relay operation with a multimeter or scan tool activation test.

🔧 DIY Diagnosis: Step-by-Step

Follow this diagnostic flow for P0380 (Misfire & Ignition / Crank-Cam Position Sensors). Start at Step 1 and work your way down — the most likely fixes are listed first.

If the Check Engine Light is FLASHING, stop driving immediately — this means catalytic converter damage is occurring right now
Check for cylinder-specific misfire codes (P0301–P0308) to identify which cylinder(s) are affected
Remove and inspect spark plugs — look for fouling, cracking, excessive gap, or oil contamination
Swap ignition coils between cylinders — if the misfire moves to the new cylinder, the coil is bad
Smoke test the intake for vacuum leaks, especially near the intake manifold gasket
If plugs, coils, and vacuum are all good, perform a compression test to check for internal engine damage

📊 Common Causes & Repair Costs

For P0380, here are the most likely root causes ranked by how often mechanics see them, plus typical repair costs for each.

Rank	Cause	Frequency	Typical Cost
#1	Worn or fouled spark plugs	35%	—
#2	Failed ignition coil	25%	—
#3	Vacuum leak	15%	—
#4	Clogged or failed fuel injector	12%	—
#5	Crankshaft or camshaft position sensor failure	8%	—
#6	Timing chain/belt issue or low compression	5%	—

Category Repair Cost Range (Misfire & Ignition / Crank-Cam Position Sensors)

DIY / Best Case:	$50
Independent Shop:	$300
Dealer / Worst Case:	$1500

Costs include parts + labor. Actual price varies by make, model, and your location.

🚨 Address Immediately

Can you drive? Limited — A steady Check Engine Light with misfire means drive gently to a shop. A FLASHING CEL means pull over and stop — you risk destroying the catalytic converter. Do not drive at highway speeds with an active misfire.

ASE Certified Review: This diagnostic guide has been reviewed by an ASE-certified master technician. Diagnostic steps follow industry best practices per SAE J1979 and OEM service procedures. Always verify with a qualified mechanic before performing repairs.

Technician's Notes: Glow plug codes are critical for diesel engines in cold climates. Even one failed glow plug can cause hard starting and white smoke. Best practice: replace all glow plugs as a set when one fails — they share the same mileage and the rest will likely fail soon.

Estimated Repair Cost

Typical repair: $50–$500 (Parts + Labor) · Costs vary by make/model and location

🔌 Don't Pay $150 for a Code Read — Diagnose It Yourself

Dealerships charge $100-$200 just to scan your car and read the code. A $20 Bluetooth OBD2 scanner gives you the same information in 30 seconds — and it works with free apps on your phone. Read and clear codes yourself before deciding if you need a mechanic.

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Affiliate disclosure: We may earn a commission at no extra cost to you.

Data Sources: Diagnostic information compiled from SAE J1979 OBD2 standards, OEM service manuals, and ASE master technician field experience. Reviewed for technical accuracy. Repair cost ranges are national estimates and vary by location. Always verify with a qualified mechanic.

❓ Frequently Asked Questions

Can I drive with a misfire code (P03xx)?

A steady CEL misfire: drive gently to a repair shop within a day or two. A FLASHING CEL: pull over immediately and have the vehicle towed. Continuing to drive with a flashing CEL will destroy your catalytic converter.

How much does it cost to fix a misfire?

Spark plugs: $50–$150 (full set). Ignition coil: $50–$120 each. Vacuum leak repair: $50–$200. Fuel injector: $100–$400. Major repairs (timing chain, compression): $500–$2,000+.

What's the difference between P0300 and P0301?

P0300 means random or multiple cylinders are misfiring — the problem isn't isolated to one cylinder. P0301–P0308 point to a specific cylinder, making diagnosis much easier.

Can bad gas cause a misfire code?

Yes, contaminated or old gasoline can cause misfires, especially if water is present. Try adding fuel system cleaner and filling up with fresh premium fuel from a top-tier station.

Can I just replace one spark plug or coil?

Technically yes, but it's best practice to replace all spark plugs at the same time since they wear evenly. For coils, you can replace just the failed one, but keep in mind the others may fail soon.