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.
General code reference. Confirm the definition and diagnostic procedure for your vehicle's year, model and engine. A stored code alone does not identify a failed part.
Affected components
- Glow plug indicator
Possible causes to check
These are possible checks, not a ranked diagnosis. Follow the vehicle manufacturer's test procedure before replacing parts.
- Short to B+
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Possible 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
Diagnostic notes
- The malfunction indicator lamp may illuminate
Related codes
Sources
Check each reference's vehicle and model-year scope. General background links do not establish which fault is most likely on your vehicle.
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.