Engine-CodesMercury – P1931 Mercury

P1931 Mercury Code - Fuel Additive Pump Control Circuit/Open

Quick Answer

The P1931 diagnostic trouble code (DTC) for Mercury vehicles relates to the Fuel Additive Pump Control Circuit being open or malfunctioning. Common causes include Faulty Wiring: The most common cause of the P1931 code is faulty wiring or connectors in the fuel additive pump control circuit, Malfunctioning Relay: A malfunctioning relay that controls the fuel additive pump can also trigger this code, Defective Fuel Additive Pump: The fuel additive pump itself may be defective or malfunctioning, leading to the open circuit 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
P1931 Mercury indicates Fuel Additive Pump Control Circuit/Open.
Common causes
Common causes include Faulty Wiring: The most common cause of the P1931 code is faulty wiring or connectors in the fuel additive pump control circuit, Malfunctioning Relay: A malfunctioning relay that controls the fuel additive pump can also trigger this code, Defective Fuel Additive Pump: The fuel additive pump itself may be defective or malfunctioning, leading to the open circuit 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 Sep 09, 2024
💬 Need more help? Ask Auto Expert for instant answers — it's free!
AutoCodes App

Fix Your Car Smarter

Try the New AutoCodes App!

Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.

AutoCodes App on Google Play

Code P1931 Mercury Description

The P1931 diagnostic trouble code (DTC) for Mercury vehicles relates to the Fuel Additive Pump Control Circuit being open or malfunctioning. This code typically indicates a problem with the fuel additive system, specifically the pump control circuit. The fuel additive pump is responsible for injecting fuel additives into the fuel system to improve efficiency and reduce emissions. When the control circuit is open, it means that there is a break or disconnection in the wiring or electrical components that control the pump's operation.

OBDII Code P1931 Mercury - Fuel Additive Pump Control Circuit/Open
P1931 Mercury Code - Fuel Additive Pump Control Circuit/Open

Common Causes of P1931 Mercury

  1. Faulty Wiring: The most common cause of the P1931 code is faulty wiring or connectors in the fuel additive pump control circuit.
  2. Malfunctioning Relay: A malfunctioning relay that controls the fuel additive pump can also trigger this code.
  3. Defective Fuel Additive Pump: The fuel additive pump itself may be defective or malfunctioning, leading to the open circuit code.
  4. Corrosion or Damage: Corrosion or physical damage to the wiring or connectors can disrupt the flow of electricity and cause the circuit to open.
  5. Electrical Issues: General electrical issues within the vehicle's system, such as a blown fuse or poor ground connection, can also contribute to the P1931 code.

Symptoms of P1931 Mercury

  1. Check Engine Light: The most common symptom associated with the P1931 code is the illumination of the check engine light on the vehicle's dashboard.
  2. Decreased Fuel Efficiency: A malfunctioning fuel additive pump control circuit can lead to decreased fuel efficiency, as the additives may not be injected into the fuel system properly.
  3. Rough Idling: The engine may experience rough idling or hesitation when the fuel additive system is not functioning correctly.
  4. Failed Emissions Test: If the vehicle's emissions are affected by the issue, it may fail emissions tests due to increased emissions levels.
  5. Engine Performance Issues: In severe cases, the vehicle may experience performance issues such as hesitation, stalling, or lack of power due to the fuel additive system malfunction.

How to Fix P1931 Mercury

  1. Diagnose the Issue: The first step in repairing the P1931 code is to diagnose the exact cause of the open circuit. This may involve using a diagnostic scanner to retrieve the specific fault codes and testing the wiring and components of the fuel additive pump control circuit.
  2. Repair or Replace Wiring: If faulty wiring or connectors are identified as the issue, repair or replace the damaged components to restore the circuit's integrity.
  3. Test and Replace Relay: Test the relay that controls the fuel additive pump and replace it if necessary to ensure proper operation.
  4. Check Fuel Additive Pump: Inspect the fuel additive pump for any signs of damage or malfunction. Replace the pump if it is found to be defective.
  5. Clear Codes and Test Drive: After completing the repairs, clear the fault codes from the vehicle's system and test drive the vehicle to ensure that the issue has been resolved.

Cost to Fix P1931 Mercury

The typical repair costs for addressing the P1931 code on a Mercury vehicle can vary depending on the specific cause of the issue and the extent of the repairs needed. In general, the cost of parts for replacing wiring, connectors, relays, or the fuel additive pump itself can range from $100 to $500. Labor costs at auto repair shops typically range from $80 to $150 per hour, with the total repair time depending on the complexity of the issue and the technician's experience. Overall, the total cost of repairing the P1931 code can range from $200 to $1000 or more, depending on the factors mentioned above. It is advisable to consult with a qualified mechanic or dealership for a more accurate estimate based on the specific vehicle make and model.

Need more information about the P1931 Mercury code?

Need more information on how to fix the P1931 Mercury code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P1931 Mercury code diagnosed by a professional: Find a repair shop in your area

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 P1931 Mercury Code

No Frequently Asked Questions about P1931 Mercury Code found.

Discuss the causes and fixes for P1931 Mercury OBDII Code

Code P1931 Mercury comments

No comments found for this page.