P0609
Control Module VSS Output B
A fault is detected on the secondary vehicle speed signal output (VSS B) that the ECU sends to other modules (instrument cluster, ABS, transmission). Output level inconsistent with the internal speed value.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Symptoms
- Check engine light on
- Possible limp mode or no-start
- Multiple follow-up faults across modules
- Reset/relearn may be needed after repair
Common causes
Ordered by how often each turns out to be the cause.
- Output driver faultCommon
Parts involved
- Control Module VSS Output B
P0609 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.