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
Open circuit between throttle body 6-pin harness connector terminal "E" (Brown wire) and PCM 104-pin harness connector terminal No. 36 (Brown/Black wire)
PCM malfunction
Short to power circuit between throttle body 6-pin harness connector terminal "C" (Gray wire) and PCM 104-pin harness connector terminal No. 63 (Brown/Yellow wire)
TP sensor No. 2 malfunction