DIAGNOSIS The parallel communication link is failing. This is almost always due to incorrect cable connection sequence, mismatched models, or one generator not being in parallel mode.
FIX Adhere to this exact procedure. First, both generators must be Champion Pure Sine Inverter models with a parallel port. Second, start both generators separately and let them run for one minute. Third, on both units, press the 'Parallel' button on the control panel. The parallel icon should illuminate steadily. Fourth, with both units OFF, connect the parallel cable securely to both units. Fifth, start the master generator first, then the slave.
IF THAT DIDN'T WORK The 50-amp parallel cable itself may be faulty. Inspect the cable ends for bent pins or corrosion. Test with a known-good cable. Also, ensure both generators are on a level surface; a significant tilt can disrupt the internal current sharing logic.
HEADS UP You cannot parallel a dual-fuel model running on propane with a model running on gasoline. For stable parallel operation, both units must be using the same fuel type.