Engine-CodesGeneric – P1934

P1934 Code - Fuel Additive Pump Control Circuit High

Quick Answer

The P1934 diagnostic trouble code (DTC) indicates that there is a high voltage condition detected in the fuel additive pump control circuit. Common causes include Faulty Fuel Additive Pump: The fuel additive pump itself may be malfunctioning, causing the high voltage condition in the control circuit, Wiring Issues: There could be a short or open circuit in the wiring harness that connects the fuel additive pump to the vehicle's electrical system, Corrosion: Corrosion or damage to the electrical connectors or terminals in the fuel additive pump control circuit can also trigger this code. 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
P1934 indicates Fuel Additive Pump Control Circuit High.
Common causes
Common causes include Faulty Fuel Additive Pump: The fuel additive pump itself may be malfunctioning, causing the high voltage condition in the control circuit, Wiring Issues: There could be a short or open circuit in the wiring harness that connects the fuel additive pump to the vehicle's electrical system, Corrosion: Corrosion or damage to the electrical connectors or terminals in the fuel additive pump control circuit can also trigger this code.
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 Aug 19, 2024
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Code P1934 Description

The P1934 diagnostic trouble code (DTC) indicates that there is a high voltage condition detected in the fuel additive pump control circuit. This circuit is responsible for controlling the fuel additive pump, which is used to inject fuel additives into the fuel system for various purposes such as cleaning and lubrication. When this code is triggered, it can potentially lead to issues with fuel efficiency, engine performance, and emissions.

OBDII Code P1934 - Fuel Additive Pump Control Circuit High
P1934 Code - Fuel Additive Pump Control Circuit High

Common Causes of P1934

  1. Faulty Fuel Additive Pump: The fuel additive pump itself may be malfunctioning, causing the high voltage condition in the control circuit.
  2. Wiring Issues: There could be a short or open circuit in the wiring harness that connects the fuel additive pump to the vehicle's electrical system.
  3. Corrosion: Corrosion or damage to the electrical connectors or terminals in the fuel additive pump control circuit can also trigger this code.
  4. Faulty Control Module: The control module responsible for regulating the fuel additive pump may be faulty, leading to a high voltage condition.

Symptoms of P1934

  1. Check Engine Light: The most common symptom associated with this code is the illumination of the check engine light on the vehicle's dashboard.
  2. Reduced Fuel Efficiency: The vehicle may experience a decrease in fuel efficiency due to improper functioning of the fuel additive pump control circuit.
  3. Rough Idle: The engine may idle roughly or inconsistently, leading to a shaky or unstable driving experience.
  4. Engine Misfires: The engine may misfire or hesitate during acceleration, causing a loss of power and performance.
  5. Emissions Issues: The vehicle may fail emissions tests due to the improper injection of fuel additives into the fuel system.

How to Fix P1934

  1. Diagnose the Issue: Use a diagnostic scan tool to retrieve the specific trouble code and pinpoint the exact cause of the high voltage condition in the fuel additive pump control circuit.
  2. Inspect Wiring: Inspect the wiring harness for any signs of damage, corrosion, or loose connections. Repair or replace any damaged wiring as needed.
  3. Test Fuel Additive Pump: Test the fuel additive pump to ensure it is functioning properly. Replace the pump if it is found to be faulty.
  4. Check Control Module: Test the control module to determine if it is sending the correct signals to the fuel additive pump. Replace the control module if necessary.
  5. Clear Codes: After making the necessary repairs, clear the DTC and reset the vehicle's computer to ensure the issue has been resolved.

Cost to Fix P1934

The typical repair costs for addressing a P1934 code can vary depending on the specific cause of the issue. In general, the cost of parts for a fuel additive pump control circuit repair can range from $150 to $500, while labor costs can range from $100 to $300. However, it's important to note that labor rates at auto repair shops can vary, and additional diagnostic time may be needed to pinpoint the exact cause of the problem. It's recommended to obtain quotes from local shops for a more accurate estimate.

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Code P1934 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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