Engine

P037E — Glow Plug Sense Circuit Low

Severity: low Safe to drive

What P037E means

The engine control module or glow plug control module monitors voltage and current in the glow plug circuit. P037E sets when the feedback signal falls below the expected range. Typical reasons are an open circuit, poor connection, a failed glow plug or a faulty control module. Glow plugs warm the combustion chambers to help a diesel start when cold.

Symptoms

  • Hard starting when cold
  • Long cranking before the engine fires
  • Rough idle right after start
  • Check engine light or glow plug indicator on
  • White smoke at cold start
  • Higher fuel consumption

Possible causes

  1. Failed glow plug (open heating element)
  2. Damaged or corroded wiring and connectors in the glow plug circuit
  3. Faulty glow plug control module or relay
  4. Blown fuse in the glow plug circuit
  5. Poor ground or power supply connection
  6. Rarely, a faulty engine control module

How to diagnose

  1. Read all codes and freeze frame data and look for other glow plug or power supply codes
  2. Inspect the fuses and relay for the glow plug circuit
  3. Check connectors and harness for corrosion, breaks and heat damage
  4. Measure each glow plug's resistance with a multimeter and compare to specification
  5. Check supply voltage and ground at the glow plug control module
  6. Verify the module's output to the plugs when the ignition is switched on
  7. If plugs and wiring are good, test the control module and only then the ECM

Common fixes

  • Replace failed glow plugs, preferably as a set
  • Repair the wiring or replace damaged connectors
  • Replace the fuse after fixing the cause
  • Replace the glow plug control module or relay
  • Have the ECM diagnosed and repaired by a specialist

Questions and answers

What does P037E mean?

It means the glow plug sense circuit on a diesel engine is reading low. The cause is most often a glow plug, wiring, a connector or the control module.

Can I drive with P037E?

Usually yes, especially in warm weather. In cold weather starting can become difficult, so don't put the repair off for long.

How do I test glow plugs?

Disconnect the power feed and measure each plug's resistance with a multimeter. A plug reading open circuit or very different from the others is bad.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.