P26A1
Exhaust Aftertreatment Glow Plug Circuit Low
The aftertreatment glow plug current is below expected. Either the element is partially open or supply is undersized.
- 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.
- Partial element failure raises resistanceCommon
- Supply voltage drops under loadPossible
- Connector pins corroded - high contact resistanceLess likely
Parts involved
- Aftertreatment Glow Plug
- Supply Circuit
P26A1 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.