Diagnostic Aids

When DTC 71 is latched with DTC 18 or DTC 24, it is critical to diagnose those DTCs before replacing SDM. If DTC 71 returns after SDM has been replaced, make sure DRIVER-SIDE LO and PASSENGER-SIDE LO are not less than 3 volts.

Fig 1: DTC 71 - Internal SDM Failure

Courtesy of GENERAL MOTORS CORP.