Possible Causes

WARNING: This page is about a different car, the 2002 Mazda 626 and 2001 Mazda 626. However, it is still accessible from the selected car via links, so may be relevant.

Following items are possible causes for DTC P0706:

Charging system malfunction.
TR switch malfunction.
TR switch out of adjustment.
Open in TR circuit(s) between TR switch and PCM, or TR switch and ignition switch.
Damaged connectors or wiring harness between TR switch and PCM.
PCM malfunction.