how to fix P0021 code in Toyota Corolla E170 (2013-2019)?

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, oil catch pan, engine oil, VVT solenoid replacement (if necessary).
• Ensure the vehicle is on a level surface and the engine is cool.

2. Check Engine Oil

• Sub-steps:
  1. Remove the oil dipstick and check the oil level.
  2. If the oil is dirty or low, drain the old oil into an oil catch pan and replace it with the manufacturer-recommended oil.
  3. Replace the oil filter if necessary.
  4. Recheck the oil level using the dipstick and add oil if needed.

3. Inspect and Replace VVT Solenoid

• Sub-steps:
  1. Disconnect the battery to prevent electrical shorts.
  2. Locate the VVT solenoid on the engine (usually near the camshaft cover).
  3. Remove the electrical connector from the solenoid.
  4. Unbolt the solenoid using a socket set and remove it from the engine.
  5. Inspect the old solenoid for damage or blockages.
  6. Install the new VVT solenoid, ensuring it is properly seated.
  7. Reattach the electrical connector.

4. Verify Timing Chain/Belt

• Sub-steps:
  1. Remove the engine cover (if applicable) for access.
  2. Inspect the timing chain/belt for wear, tension, and proper alignment.
  3. If misaligned or worn, replace the timing chain/belt according to manufacturer specifications.

5. Reconnect Battery and Clear Codes

• Sub-steps:
  1. Reconnect the battery terminals.
  2. Use the OBD-II scanner to clear the P0021 code from the engine computer.
  3. Start the engine and allow it to idle, checking for any unusual noises.