Code P040, Open PSPS Circuit: Action

PCM turns on MIL.

1. Checks if PI85 will cycle from high to low to high. If PI85 stays low, check for open or short to ground in circuit. If PI85 stays high, check for short to voltage in circuit.
2. Checks is circuit No. 495 is shorted to voltage or if power steering is faulty.
3. Checks if circuit No. 741 or fuse D1 is open.
4. Checks if power steering pressure switch is open.
5. Checks if circuit No. 495 is open or if PCM is faulty.

Fig 1: Code P040 Schematic, Open PSPS Circuit

Courtesy of GENERAL MOTORS CORP.

Fig 2: Code P040 Diagnostic Flow Chart, Open PSPS Circuit

Courtesy of GENERAL MOTORS CORP.