DTC P1290:00 [MZI-3.7]: Notes

WARNING: This page is about a different car, the 2009 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.

DETECTION CONDITION & POSSIBLE CAUSE

DTC P1290:00	CHT sensor circuit low input
DETECTION CONDITION	Indicates a CHT sensor circuit short to ground.
POSSIBLE CAUSE	Short to ground in wiring harness between CHT sensor terminal B and PCM terminal 2AV CHT sensor malfunction Connector or terminal malfunction
Courtesy of MAZDA MOTORS CORP.