What it means
The aftertreatment glow plug control responds to commands but the resulting current draw is out of tolerance. Worn glow plug or high-resistance contact.
At a glance
- Usually lights the check-engine light
How it works
The aftertreatment glow plug heats the exhaust on some diesels to help injected hydrocarbons ignite during DPF regeneration. The module sees that the control responds, but sets P269C when the glow plug circuit's current draw falls outside its expected range, often because the element or its connection has excessive resistance.
Common causes
Most likely first.
- Worn glow plug element raises resistance
- Corroded connector at glow plug
Symptoms
- Check-engine light
- DPF warning light
- More frequent or unsuccessful DPF regeneration
How to diagnose it
- Check freeze-frame data, commanded regeneration status, and any related glow plug codes to establish when the abnormal current was detected.
- Inspect the aftertreatment glow plug connector and nearby harness for corrosion, looseness, heat damage, or damaged wiring.
- Check the plug's current draw during a commanded test and compare it with the manufacturer's specification.
- With power isolated as directed, measure the glow plug element and connector-path resistance to distinguish a worn element from a poor contact.
- If the plug and connections pass, check relay output and supply under load against the manufacturer's specification.
Common fixes
- Clean and secure a corroded or loose glow plug connector if the terminals remain serviceable.
- Repair damaged wiring or terminals causing resistance in the circuit.
- Replace the aftertreatment glow plug if its element resistance or current draw is out of specification.
- Replace a faulty relay if its output is weak under load.
Can I keep driving?
Driving gently is generally possible if the engine runs normally, but avoid repeated short trips and heed any DPF warning. Continued failed regeneration can increase soot loading and lead to restricted exhaust flow.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.