Diagnostic Aids

Perform this test when directed by QUICK TEST. This test is only intended to diagnose the following components and circuits:

• Wiring Harness Circuits (B+, MIAH, MIAHM & VPWR)
• Manifold Intake Air Heater (MIAH)
• MIAH Relay
• Powertrain Control Module (PCM)

PCM will activate intake air heater to reduce White smoke during long idle periods under the following conditions.

• Ambient Temperature Must Be Less Than 32°F (0°C)
• Engine Oil Temperature Must Be Less Than 131°F (55°C)
• Vehicle Power (IVPWR) Must Be 11.8-15.0 Volts
• Parking Brake Must Be Applied On M/T Models
• Gearshift Lever Must Be In Park Or Neutral On A/T Models
• Glow Plugs Must Be Off

Fig 1: Identifying Manifold Intake Air Heater Circuits

Courtesy of FORD MOTOR CO.