Engine-CodesGeneric – P0640

P0640 Code - Intake Air Heater 'A' Control Circuit

Quick Answer

The P0640 code indicates a problem with the intake air heater 'A' control circuit in the vehicle. Common causes include Faulty Intake Air Heater: The intake air heater itself may be malfunctioning, causing the control circuit to trigger the P0640 code, Wiring Issues: Damage to the wiring or connectors in the intake air heater control circuit can also lead to this code being triggered, Blown Fuse: A blown fuse related to the intake air heater control circuit can prevent it from functioning properly. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P0640 indicates Intake Air Heater 'A' Control Circuit.
Common causes
Common causes include Faulty Intake Air Heater: The intake air heater itself may be malfunctioning, causing the control circuit to trigger the P0640 code, Wiring Issues: Damage to the wiring or connectors in the intake air heater control circuit can also lead to this code being triggered, Blown Fuse: A blown fuse related to the intake air heater control circuit can prevent it from functioning properly.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Table of contents Created and updated by William Orellana on Sep 11, 2024
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Code P0640 Description

The P0640 code indicates a problem with the intake air heater 'A' control circuit in the vehicle. The intake air heater is an essential component in a diesel engine that helps to warm up the air entering the engine. This is particularly important in colder climates as it aids in improving fuel combustion efficiency and reducing emissions. The control circuit is responsible for regulating the intake air heater's operation, ensuring that it functions correctly.

OBDII Code P0640 - Intake Air Heater 'A' Control Circuit
P0640 Code - Intake Air Heater 'A' Control Circuit

Common Causes of P0640

  1. Faulty Intake Air Heater: The intake air heater itself may be malfunctioning, causing the control circuit to trigger the P0640 code.
  2. Wiring Issues: Damage to the wiring or connectors in the intake air heater control circuit can also lead to this code being triggered.
  3. Blown Fuse: A blown fuse related to the intake air heater control circuit can prevent it from functioning properly.
  4. ECM/PCM Malfunction: A problem with the engine control module or powertrain control module can also cause the P0640 code to appear.

Symptoms of P0640

  1. Check Engine Light: The most common symptom associated with the P0640 code is the illumination of the check engine light on the dashboard.
  2. Reduced Engine Performance: The vehicle may experience a decrease in power and acceleration due to the intake air heater not functioning properly.
  3. Hard Starting: Cold starts may become more difficult as the intake air heater fails to warm up the air entering the engine.
  4. Increased Emissions: A malfunctioning intake air heater can lead to higher emissions output from the vehicle.

How to Fix P0640

  1. Diagnose the Issue: Use a diagnostic scanner to retrieve the trouble codes and pinpoint the exact cause of the problem.
  2. Inspect Wiring and Connections: Check the wiring harness and connectors associated with the intake air heater control circuit for any damage or loose connections.
  3. Test Intake Air Heater: Test the intake air heater to determine if it is functioning correctly or needs to be replaced.
  4. Check Fuses: Inspect the fuses related to the intake air heater control circuit to see if any are blown and replace them if necessary.
  5. Repair or Replace Components: Depending on the specific cause of the issue, repair or replace any faulty components to resolve the P0640 code.

Cost to Fix P0640

The cost of repairing a P0640 code can vary depending on the extent of the issue and the specific components that need to be replaced. On average, the repair costs for this type of problem can range from $100 to $500, including parts and labor. However, it's important to note that prices may vary based on the location of the repair shop, the make and model of the vehicle, and the complexity of the repair process. Additionally, diagnostic time and labor rates at auto repair shops can also impact the overall cost, with hourly rates typically ranging from $80 to $150. It's recommended to consult with a professional mechanic to get an accurate estimate for addressing a P0640 code.

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Code P0640 Information for Specific Makes

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

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