EMB ERJ 170/175 ER/LR
Flight Crew Air Transport Pilot (ATP)
Situational Awareness; Troubleshooting
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Returned To Gate; General Maintenance Action
Aircraft; Chart Or Publication; Human Factors; Procedure
Preparing for takeoff; after 2nd engine start & APU shutdown; received the 'ENG REF ECS DISAG' caution message during taxi. Ran QRH; which had us verify the configurations/re-enter the takeoff data. Verified we were correctly configured for departure (2 engines running; ECS ON; APU OFF; no anti-ice; FLEX ON) takeoff. This was again verified with the takeoff data message; caution message remained. Once clearing traffic and stopping; I called to speak to maintenance through dispatch. I was told to try to re-enter the takeoff data again; with dispatch; and if this didn't work a gate return would be likely. Numbers were again re-entered on Thrust TRS page. This didn't clear the message. After bringing up the ECS synoptic page; the PACK 1 FCV1 was remaining closed; despite not being selected (PACK 1 switch had been ON).Returned to the remote stand in coordination with [maintenance/operations]. Mechanics began working on aircraft. They found through the maintenance subpages not accessible to the crew; a fault regarding the pack/ram air system as to why the valve was closed. Since the aircraft had received a routine/service check the night before and hadn't flown yet; they believe that some circuit breakers were incorrectly pushed in; though they should have been pulled relating to the disabled ram air moving doors installed on the aircraft. On both CB panels; all the breakers were selected in; nothing pulled/collared; and there were no written up MEL/CDL system issues that would alert the crew to a pulled/collared CB requirement. The mechanics; however; said that per the routine check (which was signed off as completed) should have included the pulling and collaring of the 2 CB's in this system. This apparently wasn't done; and was resulting in the aircraft trying to reach an ECS system that was non-response after the final configuration before takeoff was selected. When the mechanics re-cycled the breakers at the gate; the PACK valves became responsive again; but no EICAS messages resulted. The mechanics pulled and collared the CB's relating to the ram air system; which according to the already completed routine check; made this compliant with the work that should've been done. The deeper rooted message in the system was found by the mechanics (not accessible or visible to crew) and was corrected per their own guidelines and phone coordination with maintenance. No pilot tasks involved and no extra entry was made in logbook since it was part of a previously written/accomplished task.After re-fueling and re-validation of paperwork; blocked out [2 hours] late after original scheduled departure time.If a system is engineering order/disabled; a reference for the crew with respect to CB condition would have corrected this. Adding a 'MEL' style reference would help to verify the proper CB's pull/collar; but at this time in the MEL book we have no EO/Engineering order guidance or 'O' item way to verify the work has been done.
Embraer 175 Captain reported returning to the gate after receiving 'ENG REF ECS DISAG' caution message when preparing for takeoff.