An air carrier first officer reported incomplete taxi instructions which caused a taxiway incursion.

Attributes
ACN	1717023
Time
Date	202001
Local Time Of Day	1201-1800
Place
Locale Reference	MDW.Airport
State Reference	IL
Environment
Light	Daylight
Aircraft 1
Make Model Name	Large Transport Low Wing 2 Turbojet Eng
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Flight Plan	IFR
Person 1
Function	First Officer Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 130
Events
Anomaly	ATC Issue All Types Deviation - Procedural Published Material / Policy Ground Incursion Taxiway

Narrative:

We were given the taxi instructions taxi to runway 31C via [taxiways] Y; P; G; cross [runway] 31R. When we arrived at [runway] 31C there was an aircraft holding short of [runway] 31C on [taxiway] E1 and one on E3. The captain went around the aircraft on E1 and pulled into E2 holding short of [runway] 31C. ATC then gave us a phone number to call.

Original NASA ASRS Text

Title: An Air Carrier First Officer reported incomplete taxi instructions which caused a taxiway incursion.

Narrative: We were given the taxi instructions taxi to Runway 31C via [Taxiways] Y; P; G; cross [Runway] 31R. When we arrived at [Runway] 31C there was an aircraft holding short of [Runway] 31C on [Taxiway] E1 and one on E3. The Captain went around the aircraft on E1 and pulled into E2 holding short of [Runway] 31C. ATC then gave us a phone number to call.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.