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DTC codes / P26xx · Computer and output circuits / P269E

P269EExhaust Aftertreatment Glow Plug Control Circuit High

P269E indicates that the powertrain control module (PCM) has detected an abnormally high voltage on the control circuit for a glow plug used in the exhaust aftertreatment system. This high voltage suggests an open circuit, a short to voltage, or a faulty glow plug control module, preventing proper heating of the aftertreatment component.

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

Symptoms you may notice

  • Illumination of the check engine light (malfunction indicator lamp).
  • Often no symptoms besides the warning light, especially if the aftertreatment system is not yet severely affected.
  • Reduced fuel economy or power due to the aftertreatment system not reaching optimal temperature.
  • Possible regeneration issues leading to a clogged diesel particulate filter (DPF) over time.
  • In some cases, a slight hesitation or rough running during cold starts if the glow plug also aids cold-start emissions.
  • A stored code in the PCM with no noticeable driveability complaints.

Common causes, most likely first

  1. Open circuit in the glow plug control circuit wiring, such as a broken wire or disconnected connector.
  2. Short to voltage on the control circuit, often due to chafed wiring contacting a power source.
  3. Faulty exhaust aftertreatment glow plug (open heating element).
  4. Defective glow plug control module, which may incorrectly report high voltage.
  5. Corroded or damaged electrical connectors at the glow plug or control module.
  6. PCM internal fault causing erroneous high voltage detection (rare).

How to diagnose and fix it

  1. Verify the code with a scan tool and inspect freeze-frame data to confirm the fault conditions.
  2. Perform a visual inspection of the glow plug, its wiring, and connectors for obvious damage, corrosion, or loose connections.
  3. Use a digital multimeter to check for battery voltage on the control circuit with the key on and engine off; compare to manufacturer specifications.
  4. Disconnect the glow plug and measure its resistance; an open circuit indicates a failed glow plug.
  5. Check the control circuit for continuity and shorts to voltage or ground using a multimeter and wiring diagram.
  6. If the circuit and glow plug test good, test the glow plug control module according to service information, replacing if faulty.
  7. Clear the code and perform a road test to verify the repair; reprogram the PCM if required by a technical service bulletin.

High Voltage Does Not Always Mean a Bad Glow Plug

  • A common misdiagnosis is replacing the glow plug when the actual fault is a shorted control module or a wiring harness rubbing against a hot exhaust component.
  • The code can set intermittently due to a loose ground connection at the glow plug control module, which is often overlooked during initial diagnostics.
  • On some vehicles, the exhaust aftertreatment glow plug is part of a larger emissions strategy, and a high voltage code may be triggered by a failing voltage regulator or charging system issue.
  • Always check for related codes such as P269D or P269F to determine if the fault is circuit-specific or part of a broader control module failure.
  • A faulty glow plug relay (if separate from the control module) can cause a high voltage code by sticking closed and feeding constant power to the circuit.

Can I keep driving with P269E?

You can generally continue driving with this code, but avoid long periods of idling or heavy loads until repaired, as the aftertreatment system may not function optimally and could lead to more costly emissions component damage over time.

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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