DTC P1500 - Engine Starter Signal Circuit Malfunction
WARNING: This page is about a different car, the 1996 Suzuki X-90. However, it is still accessible from the selected car via links, so may be relevant.
Turn ignition off. Disconnect PCM harness connectors. Turn ignition on. Using a voltmeter, measure voltage between ground and PCM harness connector "C", terminal No. 2 (Black/Yellow wire). See Figure. If reading is 6-12 volts while cranking engine, check for poor connections at PCM. If connections are okay, replace PCM. If reading is not a specified, repair open Black/Yellow wire.