Glow Plug Sense Circuit Low Voltage
The P037E code indicates that the glow plug control module has detected a low voltage condition on the glow plug sense circuit. This circuit monitors the voltage drop across the glow plugs during the pre-glow and post-glow cycles. A low voltage reading suggests excessive resistance or an open circuit in the glow plug wiring, a faulty glow plug, or a failing glow plug control module. This condition can lead to hard starting in cold weather and increased emissions.
01. Most Common Causes
- Open or shorted glow plug circuit wiring
- Faulty glow plug(s)
- Corroded or loose glow plug connector
- Failed glow plug control module
02. Symptoms You Will Notice
- Hard starting in cold weather
- Check Engine Light illuminated
- Excessive white smoke on startup
- Rough idle until engine warms up
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to retrieve all codes and freeze frame data.
Step 2: Visually inspect glow plug wiring and connectors for damage or corrosion.
Step 3: Measure resistance of each glow plug; typical spec is 0.5-2.0 ohms.
Step 4: Check voltage at glow plug control module connector with key on; should be battery voltage.
Step 5: If wiring and plugs are good, replace glow plug control module.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
You can drive short distances in mild weather, but starting will be difficult in cold conditions. Continued driving may cause increased emissions and potential damage to the glow plug system.
How much does it cost to fix?▼
Typical repair costs range from $50 to $150 for DIY glow plug replacement, or $200 to $500 if a shop replaces the control module.