Engine-CodesGeneric – P0644

P0644 Code - Driver Display Serial Communication Circuit

Quick Answer

The P0644 code indicates a problem with the driver display serial communication circuit in the vehicle. Common causes include Corrosion or damage to wiring or connectors in the driver display circuit, Loose connections in the circuit, Faulty driver display unit. 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
P0644 indicates Driver Display Serial Communication Circuit.
Common causes
Common causes include Corrosion or damage to wiring or connectors in the driver display circuit, Loose connections in the circuit, Faulty driver display unit.
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 12, 2024
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Code P0644 Description

The P0644 code indicates a problem with the driver display serial communication circuit in the vehicle. This circuit is responsible for transmitting data between various systems in the vehicle and the driver display, which includes important information such as speed, fuel level, and engine temperature. When this communication circuit malfunctions, it can lead to a range of issues that affect the vehicle's performance and functionality.

OBDII Code P0644 - Driver Display Serial Communication Circuit
P0644 Code - Driver Display Serial Communication Circuit

Common Causes of P0644

  1. Corrosion or damage to wiring or connectors in the driver display circuit
  2. Loose connections in the circuit
  3. Faulty driver display unit
  4. Issues with the vehicle's electronic control module (ECM)
  5. Water damage or exposure to moisture affecting the circuit

Symptoms of P0644

  1. Driver display not functioning properly or displaying incorrect information
  2. Inaccurate readings on fuel gauge or other dashboard indicators
  3. Warning lights not turning on or staying on when they shouldn't
  4. Loss of communication between various vehicle systems

How to Fix P0644

  1. Begin by inspecting the wiring and connectors in the driver display serial communication circuit for any visible damage or corrosion. Repair or replace any damaged components.
  2. Check the connections between the driver display unit and the vehicle's ECM to ensure they are secure.
  3. If the wiring and connections are in good condition, test the driver display unit itself for any faults. Replace the unit if necessary.
  4. Clear the diagnostic trouble codes from the vehicle's ECM using a scan tool and test the system to ensure the issue has been resolved.
  5. If the problem persists, consult a professional mechanic or dealership for further diagnosis and repair.

Cost to Fix P0644

The cost of repairing the driver display serial communication circuit 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 issue can range from $200 to $500, including parts and labor. However, it is important to note that labor rates at auto repair shops can vary widely, so it's advisable to check with local providers for a more accurate estimate. Additionally, the cost may be higher if the driver display unit itself needs to be replaced.

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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.

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