P05F3
Exhaust Aftertreatment Power Relay Control Circuit Open
The power relay that supplies the entire exhaust aftertreatment system (DOC, DPF, SCR sensors and heaters) reports an open control circuit. Aftertreatment effectively goes offline.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Open in relay control or harnessCommon
- Pin pushed back out of connector bodyLess likely
- Cracked solder joint inside the module or sensorLess likely
Parts involved
- Aftertreatment Power Relay
P05F3 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.