P1644 DTC Code: Everything You Need to Know


In the world of automotive diagnostics, the P1644 DTC code holds an important place. If you are encountering this code while trying to diagnose an issue with your vehicle, this article will provide an in-depth understanding of what it means, how it can affect your vehicle, and steps you can take to resolve it. So, let’s dive deep into the intricacies of the P1644 DTC code and gain insights.

Understanding the P1644 DTC Code

The P1644 DTC code refers to a problem with the signal received from the Cruise Control Module Torque Output circuit. It is a generic Powertrain Diagnostic Trouble Code (DTC) that applies to all makes and models of vehicles manufactured after 1996, when the OBD-II system was introduced.

How Does the P1644 DTC Code Manifest Itself?

When the P1644 DTC code is triggered, it typically results in the illumination of the check engine light on your vehicle’s dashboard. Additionally, you may notice a decrease in the overall performance of your vehicle, such as reduced acceleration or a change in the way the cruise control system operates.

Possible Causes of the P1644 DTC Code

Determining the root cause of the P1644 DTC code can sometimes be a challenging task. However, here are some common causes that are often associated with this error code:

  1. Faulty Cruise Control Module: The most common cause of the P1644 DTC code is a malfunctioning or faulty Cruise Control Module. If the module is not functioning correctly, it can send an incorrect signal to the vehicle’s engine management system, triggering the code.

  2. Wiring Issues: Damaged or loose wiring connections can disrupt the communication between the Cruise Control Module and the engine management system, leading to the P1644 DTC code.

  3. Software or Firmware Glitches: In some cases, the P1644 DTC code can arise due to software or firmware glitches within the Cruise Control Module. These glitches can cause incorrect data to be transmitted, resulting in the error code.

Diagnosing and Resolving the P1644 DTC Code

Diagnosing and resolving the P1644 DTC code would generally involve the following steps:

Step 1: Check for Other Error Codes

Before starting the diagnosis process, it is essential to check for any additional error codes. Sometimes, multiple error codes can be triggered simultaneously, and addressing those codes can help in resolving the P1644 DTC code more effectively.

Step 2: Inspect the Cruise Control Module

Begin by inspecting the Cruise Control Module and its wiring connections. Look for any signs of damage or loose connections. If any issues are identified, repair or replace the affected components as necessary.

Step 3: Evaluate the Software and Firmware

Once the physical components are verified, it’s crucial to evaluate the software and firmware of the Cruise Control Module. Ensure that the latest updates and patches are installed. If any glitches are detected, consider reprogramming or updating the module’s software/firmware.

Step 4: Clear the Code and Test Drive

After resolving the underlying issues, clear the P1644 DTC code using an OBD-II scanner or by disconnecting the vehicle’s battery for a few minutes. Take your vehicle for a test drive, and monitor the performance closely. If the code does not reappear and the vehicle operates normally, the issue has been successfully resolved.

Frequently Asked Questions

Now, let’s address some commonly asked questions related to the P1644 DTC code:

Q1: Can I continue driving my vehicle with the P1644 DTC code?

A1: It is generally not recommended to drive your vehicle with the P1644 DTC code present. While it may not cause an immediate breakdown, the underlying issue could potentially worsen over time, leading to more significant problems. It is best to resolve the code as soon as possible to ensure the optimal functioning of your vehicle.

Q2: Can I fix the P1644 DTC code myself, or do I need professional assistance?

A2: The complexity of resolving the P1644 DTC code may vary depending on the cause, your technical expertise, and the tools/equipment available. While some cases may be simple to fix, others may require specialized knowledge and diagnostic equipment. If you are unsure or lack experience, it’s advisable to seek professional assistance from a qualified mechanic or automotive technician.

Q3: How much does it cost to fix the P1644 DTC code?

A3: The cost of resolving the P1644 DTC code can vary depending on several factors, such as the cause of the code, the labor rates in your area, and the specific vehicle make and model. Additionally, if replacement parts are required, their costs will also factor into the overall expense. It is recommended to consult with a qualified professional to get an accurate estimate for your vehicle.


The P1644 DTC code can be a cause for concern for vehicle owners. However, armed with knowledge about its meaning, possible causes, and steps for resolution, you are now better equipped to tackle this error code head-on. Remember, diagnosing and fixing the underlying issue correctly will help ensure the optimal performance and longevity of your vehicle. If in doubt, seek professional assistance to avoid any further complications.

About author


Meet Sam Mitchell, your experienced and reliable guide in the complex world of car fault codes. With a robust career spanning over 15 years as a professional car mechanic, John has the skills, knowledge, and practical experience to help you navigate car fault issues with confidence.


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