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P0174 Cadillac Code - Fuel Trim System Lean Bank 2

Quick Answer

The Engine Control Module (ECM) controls a Closed Loop air/fuel metering system to provide the best possible combination of drivability, fuel economy, and emission control. Common causes include Dirty or Restricted Air Filter, Dirty or Faulty Mass Air Flow (MAF) Sensor, Intake Air Leaks. 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
P0174 Cadillac indicates Fuel Trim System Lean Bank 2.
Common causes
Common causes include Dirty or Restricted Air Filter, Dirty or Faulty Mass Air Flow (MAF) Sensor, Intake Air Leaks.
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.
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Code Popularity 67,234
How popular is this code, among other codes? Medium
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Table of contents Created and updated by William Orellana on Feb 23, 2023
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Code P0174 Cadillac Description

The Engine Control Module (ECM) controls a Closed Loop air/fuel metering system to provide the best possible combination of drivability, fuel economy, and emission control. The ECM monitors the Heated Oxygen Sensor (HO2S) signal voltage and adjusts the fuel delivery based on the signal voltage while in Closed Loop. A change made to the fuel delivery changes the long and short-term fuel trim values. The short-term fuel trim values change rapidly in response to the HO2S signal voltages. These changes fine-tune the engine fueling. The long-term fuel trim values change in response to trends in the short-term fuel trim. The long-term fuel trim makes coarse adjustments to fueling to re-center and restore control to short-term fuel trim. The ideal fuel trim values are around 0 %. A positive fuel trim value indicates that the ECM is adding fuel to compensate for a lean condition. A negative fuel trim value indicates that the ECM is reducing the amount of fuel to compensate for a rich condition. The Diagnostic Trouble Code (DTC) will be set when the average long-term fuel trim weighted average value is greater or less than a calibrated value.
OBDII Code P0174 Cadillac - Fuel Trim System Lean Bank 2 - AutoCodes.com
P0174 Cadillac Code - Fuel Trim System Lean Bank 2
What does this mean?

What are the Possible Causes of the DTC P0174 Cadillac?

  • Dirty or Restricted Air Filter
  • Dirty or Faulty Mass Air Flow (MAF) Sensor
  • Intake Air Leaks
  • Exhaust Gas Leaks
  • Fuel Contamination
  • Faulty or Clogged Fuel Injectors
  • Faulty Front Heated Oxygen Sensor
  • Ignition Misfiring
  • Low Fuel Pressure
  • Positive Crankcase Ventilation (PCV) Hose Leaks

How to Fix the DTC P0174 Cadillac?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

The P0174 code means that more air than gasoline is detected in the exhaust gases exiting the combustion chamber. If the P0174 is set in along with the P0171 code, it is highly likely that the problem is caused by an intake leak. If there are no intake leaks, the next step is to replace the air filter and clean the Mass Air Flow (MAF) Sensor. If the problem persists the MAF or Front Heated Oxygen (O2) Sensor will need to be replaced.

Click Here to Learn What is Bank 1 and Bank 2

There are Factory Service Bulletins for the following Cadillac models:

2000-2013 Cadillac All Models:
2000-2013 Cadillac Factory Service Bulletin OBDII Code P0174

2007 Cadillac Escalade, Escalade ESV, Escalade EXT
2007 Cadillac Escalade Factory Service Bulletin OBDII Code P0174




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What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0174 Cadillac code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0174 Cadillac code?

Need more information on how to fix the P0174 Cadillac code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0174 Cadillac 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 P0174 Cadillac Code

1. What are the common symptoms of OBDII code P0174 (Cadillac)?

Symptoms can include rough idling, poor acceleration, engine misfires, and a noticeable decrease in fuel efficiency.

2. What does the OBDII code P0174 (Cadillac) indicate?

This code indicates a lean condition on Bank 2 of the engine, related to the fuel trim system.

3. What are the common causes of OBDII code P0174 (Cadillac)?

Common causes include a vacuum leak, faulty oxygen sensor, dirty or clogged fuel injectors, a failing fuel pump, or a problem with the mass airflow sensor.

4. How can I diagnose the OBDII code P0174 (Cadillac) at home?

You can start by checking for any visible signs of vacuum leaks, inspecting the oxygen sensor, cleaning the fuel injectors, and ensuring the air filter is clean.

5. Can driving with OBDII code P0174 (Cadillac) cause further damage to the vehicle?

Continued driving with this code can potentially lead to damage to the engine and catalytic converter due to improper air-fuel mixture.

6. How can I repair OBDII code P0174 (Cadillac) at a professional repair shop?

A repair shop may perform a thorough inspection using diagnostic tools to pinpoint the exact cause, and then replace or repair the faulty components accordingly.

7. Are there any DIY tips for fixing OBDII code P0174 (Cadillac)?

DIY tips include checking for loose hoses, cleaning the MAF sensor, replacing the air filter, and ensuring proper fuel quality.

8. Is it safe to drive my Cadillac with OBDII code P0174 (Fuel Trim System Lean Bank 2) illuminated?

It is generally not recommended to drive with this code illuminated, as it can lead to potential issues with engine performance and emissions.

9. How much does it typically cost to repair OBDII code P0174 (Cadillac)?

The cost of repair can vary depending on the exact cause, but it may range from a few hundred to a thousand dollars at a repair shop.

10. Will resetting the OBDII code P0174 (Cadillac) turn off the check engine light permanently?

Resetting the code may temporarily turn off the check engine light, but if the underlying issue is not fixed, the light is likely to come back on.

Discuss the causes and fixes for P0174 Cadillac OBDII Code

Submit a New Comment

  • are codes 174 and 300 related on a 04 Cadillac Deville 4.6

    Reply to Comment

  • Yes. For example, if the problem is an intake leak, that will also cause the engine to misfire and trigger the P0300 code.

    Reply to Comment
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