P2561
A/C Control Module Requested MIL Illumination
The A/C / HVAC control module has requested the ECM to illuminate the malfunction indicator (MIL) because of an emissions-relevant fault on its side. The original fault is stored in the HVAC module — this code only signals that the ECM has honoured the request.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Internal fault in the HVAC module — read its DTCsCommon
Parts involved
- Hvac Module
P2561 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.