Possible Causes

WARNING: This page is about a different car, the 2003 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.

Possible causes are:

Connector or terminal malfunction
Left OCV malfunction
Open circuit between left OCV 2-pin harness connector terminal "A" (Brown/Blue wire) and PCM 104-pin harness connector terminal No. 102 (Brown/Yellow wire)
Open circuit between main relay harness connector terminal "C" (White wire) and left OCV harness connector terminal "B" (Green/Blue wire)
PCM malfunction
Short to ground circuit between left OCV harness connector terminal "A" (Brown/Blue wire) and PCM 104-pin harness connector terminal No. 102 (Brown/Yellow wire)