P037D

Glow Plug Sense Circuit

Q: Is it safe to drive with P037D?

Yes once the engine is running — the main effect is harder cold starting and rougher cold running. Fix it before winter to avoid no-cold-start problems.

Q: Can I just clear P037D?

It returns if the glow plug or sense-circuit fault is still present. Repair the circuit first.

Diesel glow plug Generic OBD-II Medium

What it means

P037D is a diesel code meaning the glow plug sensing/feedback circuit isn't reading correctly. Glow plugs pre-heat the cylinders for cold starting, so a fault here mainly shows up as harder cold starts and rough cold running — usually from a failed glow plug, its wiring, or the glow plug control module, rather than an engine mechanical problem.

Medium

Can I keep driving? Drivable once warm — expect harder cold starting and possible rough running/white smoke until the engine warms up.

Real-world scan data

Seen in

scans in the past year

Found in

<0.1%

of scans

<0.1%

of scans that found faults

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/wait-to-start light) on
Hard starting when cold, longer cranking
Rough running and possible white smoke right after a cold start
May start and run normally once warm

Common causes

Most likely first

Faulty glow plug or glow plug sensing/feedback circuitLikely
Open, shorted, or corroded wiring in the glow plug sense circuitCommon
Poor electrical connection at a glow plug or the glow plug control moduleCommon
Faulty glow plug control moduleLess often

How to diagnose & fix

Work through it in order

Identify which glow plug/sense circuit is flagged and inspect its wiring and connectors.
Measure glow plug resistance and check for battery voltage during the pre-glow cycle.
Inspect the glow plug control module connections and grounds.
Replace the faulty glow plug or repair the sense-circuit wiring, then clear and re-test.

FAQ

Quick answers

Is it safe to drive with P037D?+

Yes once the engine is running — the main effect is harder cold starting and rougher cold running. Fix it before winter to avoid no-cold-start problems.

Can I just clear P037D?+

It returns if the glow plug or sense-circuit fault is still present. Repair the circuit first.

Read & clear P037D 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