SES MIL Evap DTC And/Or Hard To Fill - keywords emission engine evap evaporative fuel fill hard large leak p1446 p0442 p0455 pressure purge solenoid tank vacuum vent

This PI was supercede to remove the statement: please submit a product report, engineering is close to providing a fix. Please discard PIT4347C.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Some owners may comment that the SES is illuminated. During diagnosis technicians may find an EVAP DTC stored in the ECM and excessive moisture/water/corrosion at the vent valve solenoid, vent valve pipes, and/or EVAP canister. The vent valve solenoid draws fresh air from near the top of the fuel filler pipe. In some situations, it is possible that water spray from the rear wheels may be drawn in though the vent valve pipe at the top of the fuel filler pipe.

GM engineering is aware of this concern and working on a permanent correction. At this time clean and/or replace the affected components to correct the concern.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.