P0640: Intake Air Heater Control Circuit

What does P0640 mean?

P0640 is a diagnostic trouble code indicating "Intake Air Heater Control Circuit". This code relates to your vehicle's intake system and should be diagnosed to determine the root cause. The severity level helps indicate how urgently this should be addressed.

Symptoms you may notice

• Check engine light (MIL) illuminated on dashboard
• Intermittent warning lights
• Erratic gauge readings

Common causes

• Faulty intake system component
• Wiring or connector issue in the related circuit
• Failed sensor providing incorrect readings
• Software/calibration issue requiring ECU update
• Related component causing secondary fault

What should you do?

This code sits in an engine peripheral, typically emissions or forced induction. It will not take braking or steering away, but it can put the car into limp mode, cost you fuel and fail a roadworthy. Book it in rather than clearing it and hoping.