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:

Clutch switch malfunction
Connector or terminal malfunction
Open circuit between clutch switch 5-pin harness connector terminal "D" (Black wire) and ground
Open circuit in White/Green wire between clutch switch 5-pin harness connector terminal "B" and PCM 104-pin harness connector terminal No. 17
PCM malfunction
Short to ground circuit in White/Green wire between clutch switch 5-pin harness connector terminal "B" and PCM 104-pin harness connector terminal No. 17