P037E - Glow Plug Sense Circuit Low
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System
Powertrain (Engine & Gearbox)
Related Fault Codes
Technical Description
P037E is stored when the Engine Control Module (ECM) detects a low voltage condition in the glow plug feedback / sense circuit. The ECM monitors the glow plug control module or the glow plugs directly to confirm operation. If the feedback signal voltage remains below a calibrated limit (typically < 0.5V when active high is expected) for a specific duration, the code is set. This monitor ensures that the glow plug system is functioning to facilitate cold starts and support DPF regeneration cycles by increasing combustion chamber temperatures.
Possible Causes
Short to ground in the glow plug sense circuit wiring
Faulty Glow Plug Control Module (GPCM)
Defective glow plug(s) causing incorrect circuit load
Internal Engine Control Module (ECM) fault
Symptoms
Recommended Solution
- 2. 3. Measure voltage on the sense line; during activation, it should be near battery voltage (12V). 4. 5. 6. If wiring and plugs are intact, replace the Glow Plug Control Module.
Mechanic's Tip
Before replacing expensive components, always double-check wiring and connections. 80% of all sensor faults are actually due to corroded contacts or broken wires.
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