If using two separate iO2SS's in automatic (signal augmentation) mode, verify that each unit's output (green wire) is connected to the appropriate oxygen sensor signal wire leading to the PCM. Reverse the wires if the problem persists.
If using a single, dual output iO2Ss in automatic (signal augmentation) mode, your car may require two individual single output iO2SS's instead.
If using an iO2SS in manual (signal generation) mode and this error code occurs, contact support@symtechlabs.com for further support.