Conditions for Clearing the MIL/DTC

A History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
The PCM receives the clear code command from the scan tool.

Fig 1: Diagnostic Chart - DTC P1189

Courtesy of GENERAL MOTORS CORP.

Fig 2: Diagnostic Chart - DTC P1189

Courtesy of GENERAL MOTORS CORP.