P037B
Glow Plug/Heater Indicator Control Circuit High
Generic OBD-II
Common symptoms
What you'll notice
- Check and replace any faulty glow plugs or heater indicators.
- Inspect and repair any damaged or loose wiring within the glow plug or heater indicator circuit.
- Verify and replace any defective glow plug or heater indicator control module.
- Ensure the glow plug relay is functioning properly and replace if necessary.
- Consult the car or motorcycle's manufacturer service manual for further troubleshooting and diagnostic steps.
Common causes
Most likely first
- Faulty glow plug or heater indicator control module
- Loose or corroded electrical connections in the glow plug or heater indicator circuit
- Short circuit or open circuit in the glow plug or heater indicator wiring
- Malfunctioning engine coolant temperature sensor
- Faulty powertrain control module (PCM)
How to diagnose & fix
Work through it in order
- Glow plug/heater indicator light stays on constantly
- Glow plug/heater takes longer than usual to warm up
- Engine misfires or has difficulty starting
- Reduced engine power or decreased performance
- Increased fuel consumption
Read & clear P037B yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.