AutoCodes – Dodge – P0640 Dodge

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

Quick Answer

The Engine Control Module (ECM) uses an Intake Air Heater (IAH) to warm the incoming air for proper cylinder combustion. Common causes include Faulty Intake Air Heater (IAH) Relay, Faulty Intake Air Heater, Intake Air Heater Relay harness is open or shorted. 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 Dodge indicates Intake Air Heater 'A' Control Circuit.
Common causes: Common causes include Faulty Intake Air Heater (IAH) Relay, Faulty Intake Air Heater, Intake Air Heater Relay harness is open or shorted.
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.

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Code Popularity 2,088

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on May 01, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0640 Dodge 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 Dodge - Intake Air Heater 'A' Control Circuit - AutoCodes.com — P0640 Dodge Code - Intake Air Heater 'A' Control Circuit

What does this mean?

What are the Possible Causes of the DTC P0640 Dodge?

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

How to Fix the DTC P0640 Dodge?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0640 Dodge code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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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.

Frequently Asked Questions about P0640 Dodge Code

1. What does the OBDII code P0640 for Dodge mean?

The code P0640 indicates a problem with the Intake Air Heater 'A' Control Circuit in a Dodge vehicle.

2. What are the common symptoms of a P0640 code in a Dodge?

Common symptoms of a P0640 code in a Dodge include rough idle, decreased fuel efficiency, and the Check Engine Light being illuminated.

3. What are the possible causes of a P0640 code in a Dodge?

Possible causes of a P0640 code in a Dodge include a faulty intake air heater relay, wiring issues, a malfunctioning intake air heater control module, or a blown fuse.

4. How can I diagnose a P0640 code in my Dodge?

Diagnosing a P0640 code in a Dodge involves checking the intake air heater relay, inspecting the wiring for any damage, testing the intake air heater control module, and checking the fuse for the intake air heater system.

5. How can I repair a P0640 code in my Dodge?

To repair a P0640 code in a Dodge, you may need to replace the faulty intake air heater relay, repair any damaged wiring, replace the intake air heater control module, or replace a blown fuse.

6. Can a P0640 code cause damage to my Dodge if left untreated?

While a P0640 code may not cause immediate damage to your Dodge, it can lead to poor engine performance and decreased fuel efficiency over time if left untreated.

7. Can I drive my Dodge with a P0640 code?

It is not recommended to drive your Dodge with a P0640 code, as it can lead to decreased performance and potential long-term damage to the engine.

8. How much does it typically cost to repair a P0640 code in a Dodge?

The cost of repairing a P0640 code in a Dodge can vary depending on the specific issue causing the code, but it may range from $100 to $500 or more for parts and labor.

9. Can I reset the Check Engine Light after repairing a P0640 code in my Dodge?

After repairing a P0640 code in a Dodge, you can reset the Check Engine Light using an OBDII scanner to clear the stored trouble codes and turn off the light.

10. Is it possible to prevent a P0640 code from occurring in my Dodge?

To prevent a P0640 code from occurring in your Dodge, it is recommended to perform regular maintenance, address any engine performance issues promptly, and keep the intake air heater system in good condition.