P037E
Glow Plug Sense Circuit Low
Diesel glow plug / cold start
Generic OBD-II
High
What it means
P037E is a diesel code meaning the glow plug sense circuit is reading a voltage that is too low. Glow plugs pre-heat the combustion chambers to help a cold diesel start, so this fault mostly shows up as hard cold starting, rough running just after start-up, and cold-start smoke — the engine typically runs fine once it warms up.
High
Can I keep driving? The engine runs normally once warm; the main effect is hard cold starting and rough cold running, so it's a cold-weather concern rather than a breakdown risk.
Common symptoms
What you'll notice
- Check-engine (or glow plug) light on
- Hard starting when the engine is cold
- Rough idle and misfire just after a cold start
- White or grey smoke on cold start-up
Common causes
Most likely first
- Failed glow plug (open or low resistance)Likely
- Open or shorted glow plug wiring/harnessCommon
- Poor or corroded connection at the glow plug or moduleCommon
- Faulty glow plug control moduleLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and identify which glow plug circuit is flagged.
- Inspect the glow plug harness and connectors for damage or corrosion.
- Measure each glow plug's resistance and compare against spec.
- Check the glow plug control module supply, ground, and control signals.
- Replace the faulty glow plug or module; clear and re-test.
FAQ
Quick answers
Is it safe to drive with P037E?+
Yes, once the engine is running. Glow plugs mainly assist cold starting, so the concern is hard starts and rough cold idle rather than driving safety.
Can I just clear P037E?+
It will return the next time the ECM checks the glow plug circuit. Fix the plug or wiring first, then clear it.
Related codes
Often seen with P037E
Read & clear P037E yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX