P0640 GMC - Intake Air Heater 'A' Control Circuit

Repair Importance Level: 3/3
Repair Difficulty Level: 2/3   
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P0640 GMC 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

First diagnose P0640 GMC code

    Check the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded terminals.

Cost of diagnosing the P0640 GMC code

    Labor: 1.0

    The cost of diagnosing the P0640 GMC code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle's make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.

P0640 GMC 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

P0640 GMC More Information

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