how to fix P0174 code in Toyota Highlander XU70 (2020-Present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Repair Air Intake System

• Sub-step 1: Visually inspect the air intake duct and connections for cracks or disconnections.
• Sub-step 2: Tighten any loose clamps and replace damaged components.
• Sub-step 3: Use a vacuum gauge to check for vacuum leaks; fix any identified leaks.

3. Clean or Replace MAF Sensor

• Sub-step 1: Remove the MAF sensor from the air intake duct. (Tools: Torx screwdriver)
• Sub-step 2: Use MAF cleaner to gently clean the sensor elements; allow it to dry completely.
• Sub-step 3: If damaged, replace the MAF sensor with a new unit, ensuring proper torque on fasteners.

4. Check Fuel System

• Sub-step 1: Connect a fuel pressure gauge to the fuel rail.
• Sub-step 2: Start the engine and monitor the fuel pressure; refer to specifications (typically around 50-60 psi).
• Sub-step 3: If pressure is low, check the fuel pump and filter for clogs or malfunctions and replace as needed.

5. Inspect and Replace Oxygen Sensors

• Sub-step 1: Locate the oxygen sensors (pre-catalytic converter) on Bank 2.
• Sub-step 2: Disconnect the wiring harness and use an O2 sensor socket to remove the sensor.
• Sub-step 3: Install the new oxygen sensor and reconnect the wiring harness.