Test Description

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

1. 2. Checks that both the ON and OFF states are commanded. Repeat the commands as many times as necessary.
2. 3. This check can detect a partially shorted coil which would cause excessive current flow. Leaving the circuit energized for 2 minutes allows the coil to warm up. When warm, the coil may open, and the amps drop to zero, or the coil may short, and the draw is more than 0.75 A.
3. 14. If no trouble is found in the control circuit or in the connection at the PCM, the PCM may be malfunctioning. However, this is an extremely unlikely failure.

Fig 1: DTC P1656 (Steps 1-9)

Courtesy of GENERAL MOTORS CORP.

Fig 2: DTC P1656 (Steps 10-16)

Courtesy of GENERAL MOTORS CORP.