OBD-II code · Powertrain (generic)
P037B Glow Plug/Heater Indicator Control Circuit High
Glow plug indicator drive line stuck high — short to B+. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
Is it safe to drive with P037B?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyShort to B+
- Less likelyConnector pins corroded - high contact resistance
- Less likelySupply wire pinched against B+ source
Symptoms
- Glow plug warning light on (often orange coil symbol)
- Hard cold start or no start in cold weather
- White smoke from exhaust during warm-up
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.3–1.5 h
- Emissions test
- Usually unaffected
- Parts involved
- Glow Plug Indicator
Related codes
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.