Ecu Power Source Circuit

Remove the power seat position ECU with connectors still connected. See Fig 1. Measure the voltage between connector P18 terminals No. 8 (+B) and 7 (GND) of the power seat position ECU connector. See CONNECTOR IDENTIFICATION . If the voltage is 10-14 volts, check the power seat position ECU. If the voltage is not as specified, go to the next step.
Measure the resistance between connector P18 terminal No. 7 (GND) of the power seat position ECU connector and body ground. If the continuity is below 1 ohm, go to the next step. If the continuity is not as specified, repair or replace the wiring harness or connector.
Remove the power seat position ECU with connectors still connected. Check the voltage between connector P19 terminals No. 9 (SYSB) and 13 (SGND) of the power seat position ECU connector. If the voltage is 10-14 volts, check the power seat position ECU. If the voltage is not as specified, go to the next step.
Measure the resistance between connector P19 terminal No. 13 (SGND) of the power seat position ECU and body ground. If the continuity is below 1 ohm, go to the next step. If the continuity is not as specified, repair or replace the wiring harness or connector.
Check the D P/SEAT (30-amp) located in the driver side junction block, for driver seat, or the P P/SEAT fuse (30-amp) located in the passenger side junction block, for passenger seat, and the DOME (10-amp) fuse located in the passenger side junction block. If the results are OK, check and repair the connector between the power seat position ECU and battery. If the results are not good, check for a short in all the wiring harness and components connected to the D P/SEAT (30-amp) located in the driver side junction block, for driver seat, or the P P/SEAT fuse (30-amp) located in the passenger side junction block, for passenger seat, and the DOME (10-amp) fuse located in the passenger side junction block, and repair them.

Fig 1: Identifying ECU Power Source Circuit