Circuit Test: GS400

Remove starter relay from underhood junction block. Check for battery voltage at junction block relay cavity terminal No. 5. Turn ignition to START. Check for battery voltage at junction block relay cavity terminal No. 1.
Turn ignition off. Check for continuity between junction block relay cavity terminal No. 2 and ground. Check for continuity between junction block relay cavity terminal No. 5 and starter terminal No. 1 (Black wire).
Using DVOM, backprobe Natural ECM 28-pin connector E5 terminal 2 (Black wire). See Fig 1. Check for voltage with ignition in START position.
Check for faulty starter relay, park/neutral position switch, or wiring harness. Repair as necessary.

Fig 1: Measuring Voltage At ECM Connector E5 (GS300 & GS400)