2020-2025 Buick Encore GX & Chevrolet Trailblazer AWD Fuel Pump: Stalling, Fuel Gauge Issues, and Replacement Guide

Compatibility Warning: AWD Models Only

Symptoms of a Failing Fuel Pump

A failing fuel pump can cause a variety of problems, from minor annoyances to leaving you stranded. Here are the most common signs that your fuel pump may be going bad:

• Engine Stalling: The engine may stall unexpectedly while driving, especially at low speeds or when idling. This can happen if the pump overheats or momentarily stops supplying fuel.
• Difficulty Starting: The engine may take longer than usual to start, requiring extended cranking. This happens when the pump isn't building up enough pressure in the fuel lines when you turn the key.
• Loss of Power: You may notice the vehicle feels sluggish, hesitates during acceleration, or struggles to maintain speed on the highway or when going uphill. This is a classic sign that the engine is being starved of fuel under load.
• Engine Sputtering or Misfiring: The engine may run rough, sputter, or jerk at consistent speeds. This indicates an inconsistent fuel supply.
• Whining Noise From Fuel Tank: A loud, high-pitched whining or buzzing sound from the rear of the vehicle is a common sign of a failing fuel pump motor. A healthy pump makes a quiet hum for a few seconds when you first turn the key, but a continuous, loud whine while the engine is running is a bad sign.
• Inaccurate or Erratic Fuel Gauge: Since the fuel level sensor is part of the pump module, a faulty sensor can cause the fuel gauge to read empty when full, full when empty, or jump around randomly.

Known Issues, TSBs, and Recalls

While there are no widespread recalls specifically for the fuel pump on these vehicles, there are related issues and owner complaints worth noting.

TSB for Fuel Rail Leak (Potential Fire Risk)

A notable issue for both the 2020-2021 Buick Encore GX and the 2021 Chevrolet Trailblazer with the 1.3L engine is a potential fuel leak from the fuel rail. GM issued Technical Service Bulletin (TSB) PIP5765 to address this.

• Symptom: A strong smell of gasoline in the engine bay or inside the passenger compartment.
• Cause: The fuel rail may develop a leak, which can be a significant fire hazard.
• Solution: Dealers are instructed to inspect the fuel system for leaks and replace any faulty components. If you smell gas, you should have your vehicle inspected immediately.

Fuel Gauge Complaints

Some owners have reported issues with the fuel gauge not reading correctly. This can be caused by a failure of the fuel level sending unit, which is integrated into the fuel pump module. If your gauge is inaccurate, the entire fuel pump module often needs to be replaced to fix the problem.

Buying a Used Fuel Pump: What to Check

A used OEM fuel pump can be a reliable and cost-effective alternative to an expensive new part. Because this is a critical component, careful inspection is key. Here’s what to look for:

• Verify the Part Number: The most important step. Match the part number from the used unit to your original pump or the known OEM numbers. The latest part number is 42833707, which supersedes 42720984, 42746098, and 42783075. Ensure the seller confirms it came from an AWD model.
• Inspect the Electrical Connector: Look closely at the plastic connector on top of the pump assembly. The pins should be straight, clean, and free of any corrosion or signs of overheating (discoloration, melted plastic). A damaged connector is a major red flag.
• Check the Housing for Cracks: The plastic housing of the pump module should be free of any cracks or damage. A cracked housing could cause fuel leaks.
• Examine the Fuel Level Float Arm: The float is a small arm with a buoyant piece on the end that moves up and down with the fuel level. Make sure the arm is present, moves freely, and is not bent or broken. A damaged float arm will result in an inaccurate fuel gauge reading.
• Consider the Mileage: Fuel pumps are wear items. A pump from a low-mileage vehicle (under 75,000 miles) is a much better bet than one from a high-mileage car. Ask the seller for the mileage of the donor vehicle.

Replacement Information

Replacing the in-tank fuel pump is a moderately difficult job. While it doesn't always require specialized tools, it involves working directly with the fuel system, which carries inherent risks.

On the 2020-2025 Buick Encore GX and 2021-2025 Chevrolet Trailblazer, the fuel pump is typically accessed through a service panel located under the rear seat cushions. This avoids the much larger job of dropping the entire fuel tank. However, if an access panel is not present, the tank must be lowered for access, which significantly increases the difficulty and labor time.

• Difficulty Rating: 3 out of 5 (with access panel); 5 out of 5 (if tank must be dropped)
• Estimated Time: 1.5 - 2.5 hours
• DIY Feasible: Yes, for experienced DIY mechanics comfortable with fuel system safety procedures.

Cost Comparison

The cost to replace the fuel pump can vary significantly based on the parts used and labor rates. Here is a general breakdown:

Note: Labor costs for the Trailblazer tend to be higher than for the Encore GX according to repair estimators. Prices are estimates and will vary by location and repair shop.

Frequently Asked Questions (FAQ)