P0EC9
A/C Refrigerant Temperature Sensor B Circuit Range/Performance
The ECM detects a range/performance fault on the a/c refrigerant temperature sensor b circuit. Reading cannot be used reliably for control.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Sensor characteristic driftedCommon
- Sensor mounting displacedPossible
- Sensor element aged beyond calibration windowLess likely
Parts involved
- AC Refrigerant Temp Sensor B
- Wiring Harness
P0EC9 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.