Glow Plug Sense Circuit Malfunction
The P037D code indicates a problem in the glow plug sense circuit, which monitors the current or voltage of the glow plugs during preheating. This circuit helps the engine control module (ECM) verify proper glow plug operation. A fault can be due to a failed glow plug, open or short in the wiring, or a defective glow plug control module. This issue primarily affects diesel engines, leading to hard starting in cold conditions.
01. Most Common Causes
- Failed glow plug(s)
- Open or short circuit in glow plug wiring
- Faulty glow plug control module
- Corroded or loose electrical connectors
02. Symptoms You Will Notice
- Hard starting, especially in cold weather
- Check Engine Light illuminated
- Excessive white smoke on startup
- Rough idle after cold start
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to confirm P037D and check for related codes.
Step 2: Visually inspect glow plug wiring and connectors for damage or corrosion.
Step 3: Test glow plug resistance with a multimeter (typically 0.5-2 ohms).
Step 4: Check glow plug control module for proper voltage output.
Step 5: Clear code and test drive to see if it returns.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances, especially in cold weather, as it may cause hard starting and increased emissions. You can drive short distances if the engine starts, but repair promptly.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for parts and labor, depending on the number of glow plugs replaced and labor rates.