Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. 2. Be sure that both the ON and the OFF states are commanded. Repeat the commands as many times as necessary.
2. 9. If no trouble is found in the control circuit or the connection at the PCM, the PCM maybe malfunctioning, however, this is an extremely unlikely failure.

Fig 1: DTC P1641

Courtesy of GENERAL MOTORS CORP.