🔧 Prius - Fuel Pump Replacement

On your Prius, the fuel pump is inside the fuel tank as part of an in-tank pump/module assembly. Replacement involves accessing the pump from inside the cabin (under the rear seat), disconnecting the fuel lines and wiring, then swapping the pump/module and sealing it back up to prevent leaks and fuel smells.

Difficulty Level: Intermediate | Estimated Time: 2-4 hours

Assumption: U.S.-market Prius Five with under-seat access panel.

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⚠️ Safety & Precautions

• ⚠️ Work outside or in a very well-ventilated area—fuel vapors are flammable.
• ⚠️ No smoking, no sparks, and keep a fire extinguisher nearby.
• ⚠️ Disconnect the 12V battery negative terminal before opening fuel lines.
• ⚠️ Keep the Prius OFF (do not leave it in READY) during the repair.
• ⚠️ Clean around the pump opening—dirt falling into the tank can damage the new pump.
• ⚠️ Expect some fuel spray when disconnecting lines; use rags and eye protection.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 12mm socket
• 3/8" drive ratchet
• 3" extension for ratchet
• Torque wrench (5–30 Nm range)
• Trim removal tool set
• Phillips screwdriver #2
• Needle-nose pliers
• Fuel line quick-disconnect tool (specialty)
• Fuel pump lock ring wrench (specialty)
• Brass drift punch (specialty)
• Small hammer
• Shop rags
• Catch pan (at least 2-quart)
• Marker pen
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Fuel pump module assembly - Qty: 1
• Fuel pump module tank seal/O-ring - Qty: 1
• Fuel line O-rings (if applicable to your line style) - Qty: 1 set

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📋 Before You Begin

• 🅿️ Park on level ground, shift to Park, and set the parking brake.
• 🔑 Turn the Prius OFF and keep the key fob at least 10 feet away from the car.
• 🔋 Disconnect the 12V battery negative terminal (in the rear cargo area, right side under trim) using a 10mm socket.
• 🧼 Vacuum/clean the rear seat area so debris can’t fall into the tank.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the rear seat cushion

• Use a trim removal tool to pop the front edge of the rear seat cushion upward at the clips.
• Lift the cushion out of the car and set it aside.

Step 2: Open the fuel pump access cover

• Locate the metal access panel under the seat area.
• Remove any fasteners using a 10mm socket or Phillips screwdriver #2 (varies by cover style).
• Peel back the cover and any butyl sealant carefully using a trim removal tool.

Step 3: Disconnect the pump electrical connector

• Press the tab and unplug the connector by hand.
• Don’t pull on wires—pull on the plug body.

Step 4: Reduce fuel pressure (best-effort method)

• Place shop rags around the fuel line connection area.
• Slowly loosen the fuel line connection (next step) to let any residual pressure bleed into the rags.
• Expect a small spray—this is normal.

Step 5: Disconnect the fuel lines

• Position a catch pan under the work area and keep shop rags around the fittings.
• Use needle-nose pliers to remove any hose clamps (if your Prius uses a clamped hose on a vapor line).
• For a quick-connect line, use a fuel line quick-disconnect tool (specialty) (this tool releases the internal spring clip without breaking the connector).
• Pull the line straight off—do not twist aggressively.

Step 6: Mark the pump/module orientation

• Use a marker pen to mark the relationship between the tank opening and the pump/module top.
• This helps keep the fuel level float and line routing correct on reassembly.

Step 7: Remove the fuel pump lock ring

• Use a fuel pump lock ring wrench (specialty) to turn the ring counterclockwise and remove it.
• If you don’t have the wrench, use a brass drift punch (specialty) and small hammer to tap the ring counterclockwise. (Brass is softer and helps avoid sparks.)
• Lift the lock ring off and set it aside.

Step 8: Lift the fuel pump/module out of the tank

• Carefully lift the module straight up.
• Angle it as needed to clear the fuel level float arm without bending it.
• Let fuel drain back into the tank, then move the module to the catch pan.

Step 9: Replace the tank seal/O-ring

• Remove the old seal from the tank opening by hand.
• Wipe the sealing surface clean using shop rags.
• Install the new tank seal/O-ring evenly into its groove (no twists).

Step 10: Install the new fuel pump/module

• Lower the new module into the tank, keeping the float arm safe.
• Align it to your marker marks.
• Install the lock ring and tighten using the fuel pump lock ring wrench (specialty).
• If your lock ring uses bolts (some variants do), install and tighten evenly using a 10mm socket and torque wrench: Torque to 5.0 Nm (44 in-lbs).
• Even tightening prevents leaks and fuel smells.

Step 11: Reconnect fuel lines and electrical connector

• Reconnect fuel lines by pushing them straight on until you feel/hear a click.
• Gently tug to confirm they’re locked.
• Reconnect the electrical connector until it clicks.

Step 12: Reinstall the access cover and rear seat cushion

• Reinstall the access cover and fasteners using a 10mm socket or Phillips screwdriver #2.
• Reinstall the rear seat cushion by aligning the rear hooks first, then press down at the front until the clips snap in.

Step 13: Reconnect the 12V battery

• Reconnect the negative terminal using a 10mm socket.

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✅ After Repair

• 🧪 Prime the fuel system: press the Power button twice without pressing the brake to go to IG-ON, wait 10 seconds, then turn OFF. Repeat 2–3 times.
• 🔍 Check for leaks: remove the rear seat cushion again (quick check) and look/smell for fuel around the pump top and line connections.
• 🚗 Start normally (READY) and let it idle while you re-check for leaks.
• 📉 If you smell fuel inside after reassembly, stop and re-check the seal seating and lock ring tightness.

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💰 DIY vs Shop Cost

Shop Cost: $650-$1,200 (parts + labor)

DIY Cost: $220-$600 (parts only)

You Save: $430-$600 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 2-4 hours.

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🎯 Ready to get started?

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