Buick Enclave P1174 & P1175: Meaning, Causes, How to Fix

P1174 Buick Enclave

P1174 and P1175 are GM-specific DTCs (Diagnostic Trouble Codes). They indicate fuel bank trim issues on bank 1 and bank 2 of your Buick Enclave.

Buick Enclave P1174 + P1175 Quick Info

Buick Enclave P1174 or P1175
GM P1174 + P1175 DefinitionFuel Trim Cylinder Balance (Bank 1 or Bank 2)
SymptomsMild misfire, MIL light
Common CausesBad O2 sensors, spark plugs, or fuel injectors
Breakdown Risk?Almost Never
Repair Cost (Parts)Usually under $200
Repair DifficultyDifficult to diagnose


P1175 Buick Enclave

P1174: Fuel Trim Cylinder Balance (Bank 1)
P1175: Fuel Trim Cylinder Balance (Bank 2)

Fuel Trim Cylinder Balance

P1174 stands for Fuel Trim Cylinder Balance (Bank 1). These codes are set by your Enclave’s engine control unit (ECU) when a difference in the fuel-air mixture between cylinders of Bank 1 or 2 is detected by their respective oxygen sensors.

P1175 means the same exact thing as P1174, just for the cylinder head containing your Enclave’s second cylinder.

Bank 1 or Bank 2

If your Enclave has more than one cylinder head (“V” type engine), you’ll need to determine which bank is bank one. Bank one is almost always the cylinder head a little bit closer to the vehicle’s engine’s front (accessory side). A quick Google image search can help you verify where cylinder 1 is in your Buick Enclave’s model year and engine combo.

Inline engines only have one bank of cylinders, which means they’re not capable of getting P1175. So you don’t need to concern yourself with which side of the engine the code is on if your vehicle has an inline engine.


In most cases, there will be no noticeable symptoms associated with P1174 or P1175 in the Buick Enclave other than an illuminated check engine light. However, reduced fuel efficiency and/or engine power reduction could be present.

P1174 + P1175 Causes: Buick Enclave

The following are the most common causes of GM P1174 and P1175:

  • Faulty or contaminated oxygen sensors
  • Fuel injectors that are leaking or clogged
  • Incorrect or worn spark plugs, plug wires (if equipped), and coil packs
  • Vacuum leaks
  • Intake manifold leaks
  • Defective or dirty mass airflow (MAF) sensor
  • Dirty or failed exhaust gas recirculation (EGR) valve


P1174 P1175 Diagnosis Buick Enclave

Diagnosing P1174 and P1175 can be challenging due to the scope of potential causes. Diagnosing your vehicle will require a diagnostic scanner, an oscilloscope, and other specialized tools to troubleshoot the issue.

Replacing the upstream oxygen sensors or performing a tune-up are the most common fixes for P1174 and P1175 in the Buick Enclave.

Look at the Other Codes and TSB’s

If there are other codes stored in your Enclave’s memory, they can give valuable insight and help with diagnosing P1174 + P1175. For instance, look at the MAF sensor if there’s a MAF code. If there’s a misfire, pull the plug for the cylinder in question and inspect it.

Connect the scanner to your Enclave’s OBD-II port and retrieve all stored trouble codes, freeze frame data, and live data. This information can then be used to pinpoint the source of the problem.

You should also check for technical service bulletins (TSB) related to the specific make and model of the vehicle in question.

Perform a Visual Inspection

Perform a visual inspection of your Buick Enclave’s engine. Check the components and sensors. You should also check all wiring connections and wire harnesses for any signs of damage or corrosion. Once this has been done, you’ll need to move on to practical things you can do to clear the code (half a page down).

P1174 and P1175 Together

If your Enclave has P1174 and P1175 together, the O2 sensors are likely fine. It’s also not a spark plug issue since they shouldn’t simultaneously go bad on both sides of the engine.

When these codes are together, they’re most likely caused by a vacuum leak or a dirty MAF.

Common Buick Enclave P1174 + P1175 Fixes

The easiest way to fix these codes is to use a quality scanner to see what’s going on in your vehicle’s engine. The video above shows how to do that.

Here are the most common quick fixes for these codes in the Enclave.

  • Replacing the spark plugs
  • Replacing the upstream O2 sensor(s)
  • Cleaning the fuel injection system
  • Cleaning the MAF Sensor