What it means
Glow plug sense line below lower plausibility — short to ground. 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.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The glow plug sense circuit feeds the module feedback about glow plug current draw. P037E sets when the sensed line falls below its expected range, commonly because the wire is shorted to ground or its connection is faulty.
Common causes
Most likely first.
- Short to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
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
How to diagnose it
- Record freeze-frame data and compare glow plug command with sense feedback when the fault is present.
- Inspect the sense wire and connectors for chafing to ground, damaged insulation, corrosion, or loose pins.
- Check whether the glow plug indicator and cold-start behavior suggest that heating is not being verified.
- With the circuit isolated as specified by the manufacturer, test the sense line for a short to ground and check its continuity.
- If wiring passes, test the sensing module and control unit against the manufacturer's specification.
Common fixes
- Repair chafed sense wiring that is shorting to ground.
- Clean or repair corroded or loose connector terminals.
- Replace a damaged section of the glow plug sense harness.
- Replace the sensing module or control unit if circuit tests confirm failure.
Can I keep driving?
The module may not correctly verify glow plug heating, so cold starts can become difficult and produce white smoke during warm-up. Avoid extended cranking in cold weather.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.