I have a 08 GMC Denali with a 6.2L. The Vehicle came to our shop with a complaint of the transmission would not shift out of first gear, and all the dash warning lights were flashing. when we got in the vehicle it started up and shifted fine no problems. We pulled codes and every module has a communication code. We cleared the codes and test drove engine ran great and the transmission is shifting smoothly. my gut is saying that it is a communication problem but we can not duplicate the problem. not sure what direction to go. Any thoughts would be great. Ill input all the codes.
engine codes P0575, P069E, P0700, P0703, P0856, P2544, U0073, U0109,
transmission U0073
ABS U0100, U0140, U0101, C0242, U2100
Airbag B0081, B0083, B0084, B1019, B1370,
BCM U0122,
DS - Driver B2555
DS- passenger B2555
ESC U0100, U0121, U0140
Fuel pump U0073, U0100
Keyless entry C0755, C0760
Rollover sensor B1011
TPM C0755, C0760
VCI B2476
OBDII P069E, P0700, P2544, U0073.
That was our first codes scan. We deleted them and can not get anything to come back.
