Checking Fuel Pressure: 2005 Toyota Highlander Guide

To check the fuel pressure on a 2005 Toyota Highlander, you will need to perform a fuel pressure test. Here is a step-by-step guide:

- Ensure the engine is off and locate the fuel pump fuse and relay. Check the fuse for continuity and replace it if necessary. Test the relay for proper operation.

- Inspect the wiring connections for any signs of corrosion, damage, or looseness.

- Relieve residual fuel pressure by following safety precautions. This step is important to reduce the risk of fire when working with the fuel system.

- Install a fuel pressure gauge at the appropriate location. Common locations include the fuel rail, fuel filter, or cold start valve.

- Start the engine and observe the gauge reading.

- Compare the reading to the manufacturer's specifications. For a 2005 Toyota Highlander, the fuel pressure should be between 304 and 343 kPa (3.1 to 3.5 kgf/cm2, or 44 to 50 psi).

- If the pressure is high, the fuel pressure regulator may need to be replaced. If the pressure is low, check the fuel hoses, connections, fuel pump, fuel filter, and fuel pressure regulator.

Checking the fuel pump operation

To check the fuel pump operation of a 2005 Toyota Highlander, you can use either of two methods: with or without a hand-held tester.

Using a hand-held tester:

• Connect the hand-held tester to the DLC3.
• Turn the ignition switch ON and push the hand-held tester main switch ON.
• Do not start the engine.
• Select the ACTIVE TEST mode on the hand-held tester.
• Refer to the hand-held tester's instruction manual for further details.
• Turn the ignition switch OFF.
• Disconnect the hand-held tester from the DLC3.

Without using a hand-held tester:

• Remove the circuit opening relay from the R/B subassy.
• Using a service wire, connect terminals FP and +B of the R/B sub-assy.
• Pay close attention to the terminal connecting position to avoid a malfunction.
• Turn the ignition switch ON and check that the fuel pump operates.
• Do not start the engine.
• Turn the ignition switch OFF.
• Remove the service wire from the R/B sub-assy.
• Install the circuit opening relay to the R/B sub-assy.

Additionally, you can perform general checks on the fuel system by ensuring there is enough fuel in the tank and verifying that the fuel pump is running. You can do this by turning the ignition switch to ON and listening for a whirring noise, indicating the pump is pressurizing the system. If there is no sound, check the EFI fuse, the circuit opening or EFI relay, and the wiring back to the fuel pump. If voltage is present at the fuel pump connector, the pump is defective. If there is no voltage, the PCM may be faulty.

Disconnecting the negative battery terminal

To check the fuel pressure on a 2005 Toyota Highlander, you will need to disconnect the negative battery terminal. Here is a step-by-step guide:

Step 1: Disconnect the negative battery terminal

• Locate the negative battery terminal. It is usually marked with a "-" symbol or a black cover.
• Loosen the nut or bolt that secures the negative battery cable to the terminal using a wrench or socket of the appropriate size.
• Carefully remove the cable from the terminal.

Step 2: Purchase a new fuel tube

It is recommended to purchase a new fuel tube (Part No. 23801-20180) for this procedure.

Step 3: Remove the fuel pipe clamp

• Locate the fuel pipe clamp No. 1 on the fuel tube connector.
• Using your fingers, pinch part A of the fuel tube connector to disconnect it from the fuel pipe.

Step 4: Install the pressure gauge

Install the pressure gauge (SST) and fuel tube connector using SST 09268-41047, 09268-45014 (09268-41250).

Step 5: Reconnect the negative battery terminal

Reconnect the negative battery cable to the terminal and tighten the nut or bolt securely.

Step 6: Operate the fuel pump

• Using a hand-held tester: Connect the tester to the DLC3, turn the ignition switch ON, and push the tester's main switch ON. Do not start the engine. Select the ACTIVE TEST mode on the tester and refer to its instruction manual for further details. Then, turn the ignition switch OFF and disconnect the tester.
• Without a hand-held tester: Remove the circuit opening relay from the R/B subassy. Using a service wire, connect terminals FP and +B of the R/B sub-assy. Turn the ignition switch ON to check that the fuel pump operates. Do not start the engine.

Step 7: Measure the fuel pressure

• Measure the fuel pressure with the engine off. The pressure should be between 304 and 343 kPa (3.1 to 3.5 kgf/cm2, 44 to 50 psi).
• If the pressure is high, replace the fuel pressure regulator. If the pressure is low, check the fuel hoses, connections, fuel pump, fuel filter, and fuel pressure regulator.

Step 8: Start the engine and measure the fuel pressure at idle

Start the engine and measure the fuel pressure again. The pressure should still be within the specified range.

Step 9: Stop the engine and check the fuel pressure

Turn off the engine and check that the fuel pressure remains within the specified range for 5 minutes after the engine has stopped. The pressure should be 147 kPa (1.5 kgf/cm2, 21 psi). If the pressure is not as specified, check the fuel pump, pressure regulator, and/or injectors.

Step 10: Disconnect the negative battery terminal and remove the pressure gauge

After completing the fuel pressure test, disconnect the negative battery cable again and carefully remove the pressure gauge and fuel tube connector to prevent gasoline from spraying.

Step 11: Reconnect the fuel inlet tube

Reinstall the fuel inlet tube (fuel tube connector) securely. Always refer to the precautions provided in the Highlander's manual before connecting the fuel tube connector.

It is important to exercise caution when working with the fuel system. Before beginning this procedure, ensure that you have the appropriate tools and safety equipment, including eye protection and gloves. Do not smoke or be near an open flame when working on the fuel system. Keep gasoline away from your skin and always wash your hands after handling fuel system components.

Removing the fuel pipe clamp

To remove the fuel pipe clamp, you will need to purchase a new fuel tube (Part No. 23801-20180). This is because the fuel pipe line may spray fuel due to retained pressure, so it is important to have a new fuel tube ready to install.

First, locate fuel pipe clamp No. 1 on the fuel tube connector. Then, using your fingers, pinch part A of the fuel tube connector to disconnect it from the fuel pipe. Be cautious as the fuel pipe line may spray fuel. Now, you can remove the fuel pipe clamp No. 1 from the fuel tube connector.

At this point, you can proceed to install the pressure gauge and fuel tube connector, as outlined in the next steps of the fuel pressure test procedure.

Disconnecting the fuel tube connector

To disconnect the fuel tube connector of a 2005 Toyota Highlander, follow these steps:

First, ensure that you have purchased a new fuel tube, as the old one cannot be reused. The part number for the fuel tube is 23801-20180.

Now, remove the fuel pipe clamp number 1 from the fuel tube connector. This will allow you to disconnect the fuel tube connector from the fuel pipe. It is important to pinch part A of the connector with your fingers, as shown in the illustration, to avoid any damage.

Please note that the fuel pipe line may spray fuel due to retained pressure. Therefore, exercise extreme caution to prevent fuel from being sprayed in the engine compartment.

After disconnecting the fuel tube connector, be sure to wipe up any gasoline that may have spilled during the process.

Now, you can proceed to install the pressure gauge and reconnect the negative battery cable.

At this point, you can operate the fuel pump by following the steps outlined in the previous section.

Finally, measure the fuel pressure and compare it to the specified range of 304 to 343 kPa (3.1 to 3.5 kgf/cm2, 44 to 50 psi).

If the pressure is outside the specified range, further inspection and adjustments are necessary.

Remember to always refer to the precautions outlined in the Highlander's manual before performing any fuel system-related tasks. Working with fuel can be dangerous, so ensure you take the necessary safety precautions.

Installing the pressure gauge

To install the pressure gauge on your 2005 Toyota Highlander, follow these steps:

• Ensure the engine is off and the ignition is off.
• Disconnect the negative battery cable.
• Locate the fuel pressure test port. It is usually located near the fuel rail. On a Toyota Highlander, it's usually located near the engine's firewall, near the intake manifold.
• Attach a fuel pressure gauge to the test port. Common gauge hookup locations are at the fuel rail, fuel filter, or the cold start valve.
• Reconnect the negative battery cable.
• Start the engine and let it run for a few minutes.
• Check the fuel pressure gauge. It should read around 44 to 50 psi with the engine running. If the reading is significantly lower, the fuel pump may need to be checked/replaced.
• Turn off the engine and remove the fuel pressure gauge. Reattach the negative battery cable.

It is important to relieve residual fuel pressure by following safety precautions before installing the fuel pressure gauge. It is advisable to have a fire extinguisher whenever opening the fuel system.

Frequently asked questions