For 4 Wheel Drive Vehicle: DTC Detecting Condition
WARNING: This page is about a different car, the 2003 Suzuki Vitara. However, it is still accessible from the selected car via links, so may be relevant.
DTC C1258 will be set when EBCM detects voltage on 4 wheel drive input circuit is neither high (near 12 V for 2WD) nor low (under 1 V for 4WD). DTC C1258 will be set when voltage on the 4WD request circuit is between 5.25 V and 3.36 V at any time.