P0640 GMC - Intake Air Heater 'A' Control Circuit

Repair Importance Level: 3/3
Repair Difficulty Level: 2/3   
Comments  |  Add Comment

Possible causes

  • Faulty Intake Air Heater (IAH) Relay
  • Faulty Intake Air Heater
  • Intake Air Heater Relay harness is open or shorted
  • Intake Air Heater Relay circuit poor electrical connection
  • Intake Air Heater harness is open or shorted
  • Intake Air Heater circuit poor electrical connection

Possible symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)

P0640 Gmc Description

The Engine Control Module (ECM) uses an Intake Air Heater (IAH) to warm the incoming air for proper cylinder combustion. The ECM grounds the control coil of the IAH relay to energize the heater during cold operation. The control module will command the IAH ON when the engine coolant temperature is below 40 C (104 F). The power to the IAH heater is supplied by the battery positive voltage circuit through the IAH relay.
OBDII Code P0640 Gmc - Intake Air Heater 'A' Control Circuit - AutoCodes.com

Need more help?

Get the P0640 Gmc code diagnosed by a professional: Find a repair shop in your area

Related Information

P0640 GMC Comments

Help us improve AutoCodes.com. Leave a comment below or tell us if the information above help you fix the code. What are the symptoms on your vehicle for the P0640 Gmc code? Have you replaced any parts?
Any information is appreciated. Thanks
Top ⇧