Sorry, the NHTSA has not posted this TSB document yet.
You can still get the detailed info from Buick for this TSB. Call your local Buick dealer's service department & ask for a copy of TSB# SB-08-06-04-041B.
GENERAL MOTORS: MALFUNCTION INDICATOR LAMP-CHECK ENGINE LIGHT ON, HESITATION, REDUCED ENGINE POWER MESSAGE, DTCS P1125, P2101, P2120, P2125 OR P2138 SET (PERFORM REPAIR AS OUTLINED). *PE