Engine-Codes.com
Engine-Codes – Generic – P120B

P120B Code - Secondary Fuel Injector Bank 1 Excessive Flow

Quick Answer

The P120B diagnostic trouble code indicates that there is excessive flow in the secondary fuel injector bank 1 of the vehicle. Common causes include Faulty fuel injector in bank 1, Wiring or connector issues in the fuel injector circuit, Engine control module (ECM) malfunction. 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
P120B indicates Secondary Fuel Injector Bank 1 Excessive Flow .
Common causes
Common causes include Faulty fuel injector in bank 1, Wiring or connector issues in the fuel injector circuit, Engine control module (ECM) malfunction.
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.
What is this?
Table of contents Created and updated by William Orellana on Sep 10, 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 P120B Description

The P120B diagnostic trouble code indicates that there is excessive flow in the secondary fuel injector bank 1 of the vehicle. This means that the fuel injector in bank 1 is delivering more fuel than necessary, which can lead to a rich fuel mixture in the engine. A rich fuel mixture can cause various issues such as decreased fuel efficiency, increased emissions, rough idling, and poor acceleration.

OBDII Code P120B - Secondary Fuel Injector Bank 1 Excessive Flow
P120B Code - Secondary Fuel Injector Bank 1 Excessive Flow

Common Causes of P120B

  1. Faulty fuel injector in bank 1
  2. Wiring or connector issues in the fuel injector circuit
  3. Engine control module (ECM) malfunction
  4. Fuel pressure regulator failure
  5. Clogged fuel filter

Symptoms of P120B

  1. Decreased fuel efficiency
  2. Rough idling or stalling
  3. Engine misfires
  4. Reduced power output
  5. Strong fuel odor from the exhaust

How to Fix P120B

  1. Diagnose the issue by performing a fuel injector flow test and inspecting the wiring and connectors in the fuel injector circuit.
  2. Replace the faulty fuel injector in bank 1 if it is determined to be the cause of the excessive flow.
  3. Check and repair any wiring or connector issues in the fuel injector circuit.
  4. Test the fuel pressure regulator and replace if necessary.
  5. Inspect and replace the fuel filter if it is clogged and contributing to the excessive fuel flow.

Cost to Fix P120B

The typical repair costs for addressing a P120B code can vary depending on the specific cause of the issue. On average, the cost of replacing a fuel injector can range from $150 to $300 per injector, not including labor costs. The total repair cost, including parts and labor, can vary between $300 and $600 or more, depending on the extent of the repairs needed. It's important to consider that labor rates at auto repair shops can vary, so it's advisable to obtain a detailed estimate from a qualified mechanic before proceeding with the repairs.

Need more information about the P120B code?

Need more information on how to fix the P120B code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P120B code diagnosed by a professional: Find a repair shop in your area

Code P120B Information for Specific Makes

  • P120B Ford — Secondary Fuel Injector Bank 1 Excessive Flow
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 P120B Code

1. What does the OBDII code P120B mean?

P120B indicates that the secondary fuel injector in Bank 1 is delivering more fuel than expected, leading to excessive flow.

2. What are the common symptoms of code P120B?

Common symptoms include poor fuel economy, rough idling, engine misfires, reduced power, and the Check Engine Light being illuminated.

3. What causes the P120B code to appear?

Potential causes include a stuck-open secondary fuel injector, a faulty fuel pressure regulator, damaged wiring or connectors, or a malfunctioning Powertrain Control Module (PCM).

4. Can I drive with the P120B code active?

Driving with this code is not recommended, as it can lead to engine damage, excessive emissions, and further issues with engine performance.

5. How do I diagnose the P120B code?

Diagnosis involves checking the secondary fuel injector for proper operation, inspecting wiring and connectors, testing fuel pressure, and using a scan tool to monitor fuel flow data.

6. How can the P120B code be fixed?

Repairs may include replacing the faulty injector, repairing damaged wiring, cleaning fuel injectors, or replacing the PCM if it is determined to be faulty.

7. Can a clogged fuel injector cause the P120B code?

No, a clogged injector typically causes insufficient fuel flow. P120B specifically refers to excessive fuel flow.

8. Is the P120B code related to a specific vehicle make or model?

This code may appear on various vehicles that utilize secondary fuel injection systems, but the exact diagnosis and repair procedures can vary by manufacturer.

9. How much does it cost to fix the P120B code?

Repair costs can range from $150 to $600 or more, depending on whether the issue is with the injector, wiring, or PCM.

10. Can a dirty fuel system trigger the P120B code?

While a dirty fuel system is not a direct cause, it can contribute to injector malfunction, which could lead to excessive fuel flow.

Discuss the causes and fixes for P120B OBDII Code

Submit a New Comment

Code P120B comments

No comments found for this page.