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DTC codes / P06xx · Computer and output circuits / P06E0

P06E0Cylinder 11 Glow Plug Control Circuit Low

P06E0 indicates that the engine control module (ECM) has detected a low-voltage condition on the control circuit for cylinder 11's glow plug, which is used to warm the combustion chamber for reliable cold starts in diesel engines. The ECM monitors the circuit and sets this code when the voltage on the control side falls below the expected threshold, often due to a short to ground, an open circuit, or a faulty glow plug.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaComputer and output circuits

Symptoms you may notice

  • Illuminated check engine light or glow plug warning light
  • Hard starting or rough idle when the engine is cold
  • Excessive white smoke from the exhaust after a cold start
  • Reduced fuel economy during warm-up
  • Engine misfire or hesitation until the engine reaches operating temperature
  • Often no symptoms besides the warning light, especially in mild climates

Common causes, most likely first

  1. Faulty glow plug on cylinder 11 (open or shorted internally)
  2. Damaged or corroded electrical connector at the glow plug
  3. Chafed or broken wire in the glow plug control circuit (short to ground or open)
  4. Failed glow plug control module (GPCM) or relay
  5. Poor ground connection for the glow plug circuit
  6. ECM software or internal driver fault (less common)

How to diagnose and fix it

  1. Inspect the glow plug connector and wiring for damage, corrosion, or loose pins; repair or replace as needed.
  2. Measure the resistance of the glow plug on cylinder 11 and compare to the manufacturer's specification; replace if out of range.
  3. Check for continuity and short to ground in the control circuit between the glow plug and the control module; repair wiring if faulty.
  4. Test the glow plug control module or relay by verifying power and ground signals; replace if defective.
  5. Clear the diagnostic trouble code (DTC) and perform a cold-start test to confirm the repair.
  6. If the code persists, check for ECM software updates or consult a dealer for advanced diagnostics.

Glow plug circuit low-voltage pitfalls

  • A low-voltage code on a glow plug circuit often results from a short to ground in the wiring harness, not a failed glow plug itself, so always inspect the harness routing near hot or moving components.
  • Cylinder 11 is typically found on high-cylinder-count diesel engines (such as V12 or inline-12 configurations), and its glow plug may be difficult to access, leading to misdiagnosis if the connector is not fully seated.
  • The ECM may set this code intermittently if the glow plug control module has a weak internal driver, even when the glow plug and wiring test good; module replacement is sometimes the only fix.
  • Do not overlook the ground path: a poor chassis ground for the glow plug control module can cause a low-voltage signal on multiple glow plug circuits, not just cylinder 11.
  • This code does not always mean the glow plug is dead; a voltage drop across a corroded connector can trigger P06E0 while the plug still functions under load.

Can I keep driving with P06E0?

You can usually drive the vehicle, but cold-start performance and emissions may suffer, and prolonged driving with a misfiring cylinder can damage the engine. Avoid heavy loads and extended idling until the fault is repaired, and address the code promptly to prevent further issues.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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