Note On Intermittents

If intermittent Code F40 is being set, manipulate related wiring while observing parameter P.2.3. If failure is induced, door reading will either stop or jump to an extreme value (zero or 100 percent). This will help isolate location of malfunction.

Fig 1: BCM Code F40, Schematic, Air Mix Door Problem

Courtesy of GENERAL MOTORS CORP.

Fig 2: BCM Code F40, Flow Chart, Air Mix Door Problem (1 of 2)

Courtesy of GENERAL MOTORS CORP.

Fig 3: BCM Code F40

Fig 4: BCM Code F40, Flow Chart, Air Mix Door Problem (1 of 2)

Courtesy of GENERAL MOTORS CORP.

Fig 5: BCM Code F40 - 1 of 2