DTC P1510: ECM (Pcm) Back-Up Power Supply Malfunction: Condition

WARNING: This page is about a different car, the 2002 Suzuki Grand Vitara. However, it is still accessible from the selected car via links, so may be relevant.

DTC is set when ECM (PCM) detects incorrect voltage at ECM (PCM) back-up power supply. Battery voltage is supplied so that diagnostic trouble code memory values are not lost when ignition is turned off. Possible cause are:

Battery voltage supply circuit malfunction.
ECM (PCM) malfunction.