P269D
Exhaust Aftertreatment Glow Plug Control Circuit Low
Voltage on the aftertreatment glow plug control line is below the expected window. 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.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
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
Common causes
Ordered by how often each turns out to be the cause.
- Control wire shorted to groundCommon
- Relay coil shortPossible
- Connector pins corroded - high contact resistanceLess likely
Parts involved
- Aftertreatment Glow Plug
- Relay
- Wiring Harness
P269D is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.