my Volvo XC90 Second Generation (2015-2024) has a check engine light and bad fuel economy

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, fuel pressure gauge, multimeter, basic hand tools.
• Disconnect the vehicle's battery to ensure safety before performing any electrical work.

2. Address Fault Codes

• Sub-steps:
  • Review the error codes retrieved from the OBD-II scanner.
  • Research and identify the necessary repairs based on the codes (e.g., P0420 for catalytic converter efficiency).

3. Inspect and Replace Components

• Sub-steps:
  • If the air filter is dirty, remove the air filter housing cover and replace the air filter with a new one.
  • For fuel pressure issues, connect the fuel pressure gauge to the fuel rail and check the pressure against specifications. If low, inspect the fuel pump and replace it if necessary.
  • If fuel injectors are clogged, remove them using a socket set and clean or replace them as required.

4. Check Exhaust System

• Sub-steps:
  • Inspect the exhaust system visually for any signs of damage or blockage.
  • If the catalytic converter is faulty, remove it using appropriate tools and replace it with a new one, ensuring proper torque on all bolts.

5. Reassemble and Reconnect

• After repairs, reassemble any removed components, ensuring all connections are secure.
• Reconnect the battery.