Engine-CodesGeneric – P1668

P1668 Code - Fuel Injector 3 Mechanical Fault

Quick Answer

The P1668 diagnostic trouble code (DTC) indicates a mechanical fault in Fuel Injector 3 in the vehicle's fuel injection system. Common causes include Clogged fuel injector: Build-up of dirt, debris, or deposits in Fuel Injector 3 can restrict fuel flow and lead to a mechanical fault, Injector driver circuit malfunction: Issues with the circuit that controls Fuel Injector 3 can prevent it from operating properly, Wiring issues: Damaged or corroded wiring connecting the fuel injector to the vehicle's electrical system can disrupt its function. 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
P1668 indicates Fuel Injector 3 Mechanical Fault.
Common causes
Common causes include Clogged fuel injector: Build-up of dirt, debris, or deposits in Fuel Injector 3 can restrict fuel flow and lead to a mechanical fault, Injector driver circuit malfunction: Issues with the circuit that controls Fuel Injector 3 can prevent it from operating properly, Wiring issues: Damaged or corroded wiring connecting the fuel injector to the vehicle's electrical system can disrupt its function.
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 09, 2024
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Code P1668 Description

The P1668 diagnostic trouble code (DTC) indicates a mechanical fault in Fuel Injector 3 in the vehicle's fuel injection system. The fuel injector is responsible for delivering the precise amount of fuel into the combustion chamber at the right time for efficient engine operation. When Fuel Injector 3 experiences a mechanical fault, it can disrupt the fuel delivery process, leading to issues with engine performance, fuel efficiency, and emissions.

OBDII Code P1668 - Fuel Injector 3 Mechanical Fault
P1668 Code - Fuel Injector 3 Mechanical Fault

Common Causes of P1668

  1. Clogged fuel injector: Build-up of dirt, debris, or deposits in Fuel Injector 3 can restrict fuel flow and lead to a mechanical fault.
  2. Injector driver circuit malfunction: Issues with the circuit that controls Fuel Injector 3 can prevent it from operating properly.
  3. Wiring issues: Damaged or corroded wiring connecting the fuel injector to the vehicle's electrical system can disrupt its function.
  4. Fuel injector failure: Over time, the internal components of the fuel injector may wear out or fail, causing a mechanical fault.

Symptoms of P1668

  1. Rough idling: A mechanical fault in Fuel Injector 3 can cause the engine to run unevenly at idle, leading to a rough or shaky idle.
  2. Engine misfires: The malfunctioning injector may result in incomplete combustion, causing the engine to misfire during acceleration or under load.
  3. Decreased fuel efficiency: A faulty fuel injector can disrupt the fuel delivery process, leading to decreased fuel efficiency and potentially higher fuel consumption.
  4. Check engine light: The illumination of the check engine light on the dashboard may indicate a problem with Fuel Injector 3, triggering the P1668 DTC.
  5. Engine performance issues: The vehicle may experience a lack of power, hesitation, or stalling due to the mechanical fault in the fuel injector.

How to Fix P1668

  1. Diagnostic testing: Use a scan tool to retrieve the P1668 code and perform a comprehensive diagnostic test to pinpoint the exact cause of the mechanical fault in Fuel Injector 3.
  2. Inspect fuel injector: Remove and inspect Fuel Injector 3 for any signs of clogging, damage, or wear. Clean or replace the injector as needed.
  3. Check injector driver circuit: Test the injector driver circuit for proper operation and repair any faults or wiring issues that may be present.
  4. Clear DTC and test drive: Clear the DTC from the vehicle's computer after making repairs, then test drive the vehicle to ensure that the issue has been resolved.
  5. Monitor performance: Monitor the vehicle's performance after repairs to confirm that Fuel Injector 3 is functioning correctly and that the P1668 DTC does not return.

Cost to Fix P1668

The cost of repairing a Fuel Injector 3 mechanical fault can vary depending on the specific cause of the issue and the labor rates at the auto repair shop. On average, the repair cost for this type of problem can range from $150 to $500, including parts and labor. However, it's important to note that labor rates can vary widely, with hourly rates typically ranging from $80 to $150. Factors such as the vehicle make and model, location, and the extent of the repairs needed can also influence the final cost. To get a more accurate estimate, it's advisable to consult with a trusted auto repair shop in your area.

Tech Notes for P1668

Before replacing the fuel injector, check the wire harness and/or replace harness if necessary.

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Code P1668 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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