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U0121 Diagnostic Trouble Code Discussion for May 2013

Lost Communication With EBCM

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Trouble Ticket Help Requests for DTC U0121
Help Request Posted
2007 GMC Yukon XL 1500 Denali 6.2L MIL Lamp on VIN: 1GKFK66857
U0121: no communication with trans. Fellow techs. We are in this one deep and need some help. The vehicle came in with the trans in limp in mode. Check engine light on, brake and abs light on, service stability light on. Gauges will fluctuate also. We checked the connector at trans and is ok. We...
May 08, 2013