P0383

Glow Plug Control Module 1 Control Circuit Low

Glow plug system (diesel) Generic OBD-II High

What it means

P0383 sets when the engine computer sees low voltage (a short to ground or open) on the control circuit for the diesel glow plug control module. Glow plugs pre-heat the cylinders for cold starting, so the main symptoms are hard cold starts, rough cold running, and white smoke — not a warm-engine no-start. It usually traces to the module, a fuse, or the control wiring.

High

Can I keep driving? The engine runs normally once warm; the main effect is hard or delayed cold starting and rough cold running until the glow plug circuit is fixed.

Real-world scan data

Seen in

619

scans in the past year

Found in

0.1%

of scans

0.2%

of scans that found faults

Appears alongside · share of P0383 scans

P0113in 15.3% of scans

P0102in 12.8% of scans

U0100in 11.5% of scans

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Check-engine light (and often the glow-plug warning light) on
Hard or delayed cold starting
Rough idle and misfire when the engine is cold
White exhaust smoke on cold start-up

Common causes

Most likely first

Faulty glow plug control module / relayLikely
Low-side control circuit shorted to ground or openCommon
Damaged, corroded, or high-resistance wiring or a blown fuse in the glow-plug circuitCommon
Failed engine control module (rare)Less often

How to diagnose & fix

Work through it in order

Read freeze-frame data and confirm the glow plug control module low-side circuit is at fault.
Check the glow-plug fuse and inspect the control module connector and wiring for shorts to ground or corrosion.
Measure the control circuit voltage from the ECM to the module.
Test the glow plug control module's operation with a scan tool.
Replace the control module or repair the wiring as indicated. Clear and re-test.

FAQ

Quick answers

Is it safe to drive with P0383?+

Yes once the engine is running — glow plugs mainly help cold starting. Expect hard cold starts and a bit of white smoke until it's repaired.

Can I just clear P0383?+

You can, but it returns until the glow plug control circuit is fixed. It also won't restore easy cold starting on its own.

Read & clear P0383 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX