1. Measure the voltage between ECM connector B2 and body ground.

Is there battery voltage?

YES | - | Check for loose connectors at ECM connector B (31P). If necessary, update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM .■
NO | - | Repair open in the wire between reverse lockout solenoid and ECM (B2).■