2004 Toyota Prius

The 2004 Toyota Prius is a hybrid vehicle powered by a 1.5-liter four-cylinder gasoline engine paired with an electric motor, delivering a combined 110 horsepower and 82 lb-ft of torque. There were no other engine or transmission options available. Known for its fuel efficiency, the Prius was popular for its innovative hybrid technology and distinctive styling. Some owners appreciate its reliability and low running costs, while others dislike its somewhat sluggish acceleration and occasionally quirky driving feel due to the hybrid system.

Electric Motor

No Issues Found

Battery

• Hybrid Battery Failure
  • Description/Symptoms: Reduced fuel economy, the engine running more often, warning lights (triangle with exclamation point, check engine), decreased acceleration, and eventually inability to start the car. The battery’s capacity degrades over time, leading to these issues.
  • Solution: Replacement of the hybrid battery pack. Sometimes individual modules within the battery can be replaced, but a full replacement is generally recommended for long-term reliability.
  • Estimated Cost to Fix: $2,000 - $4,000+
  • Recalls: None Found

Transmission

• Transaxle Failure
  • Description/Symptoms: Whining noises, difficulty shifting between drive and reverse, loss of power, or complete failure of the transaxle. Internal wear and tear and potential fluid leaks can contribute to these issues.
  • Solution: Repair or replacement of the transaxle. Depending on the severity of the damage, a rebuild might be possible, but replacement is often the more reliable option.
  • Estimated Cost to Fix: $3,000 - $5,000+
  • Recalls: None Found

Suspension

• Rear Wheel Bearing Failure
  • Description/Symptoms: Grinding, rumbling, or humming noises coming from the rear of the vehicle, especially noticeable at higher speeds. The noise may change in intensity when turning.
  • Solution: Replacement of the affected wheel bearing(s). It’s often recommended to replace both rear wheel bearings at the same time for balanced performance.
  • Estimated Cost to Fix: $200 - $400 per wheel
  • Recalls: None Found

Electrical

• Combination Meter (Dashboard Display) Failure
  • Description/Symptoms: The multi-function display on the dashboard, which shows speed, fuel level, and other vital information, may flicker, become dim, or completely fail. This is a common issue with early Prius models.
  • Solution: Replacement or repair of the combination meter. Some repair shops specialize in rebuilding these units, which can be a more cost-effective option than a full replacement.
  • Estimated Cost to Fix: $200 - $800+
  • Recalls: None Found
• Inverter Failure
  • Description/Symptoms: Warning lights (triangle with exclamation point, check engine), loss of power, and potentially the vehicle stalling. The inverter converts DC power from the battery to AC power for the electric motor.
  • Solution: Replacement of the inverter assembly.
  • Estimated Cost to Fix: $3,000 - $5,000+
  • Recalls: None Found

Exterior

• Headlight Condensation/Clouding
  • Description/Symptoms: Moisture buildup inside the headlight housing, causing clouding or reduced visibility. This is often due to failing seals or cracks in the housing.
  • Solution: Replacement of the headlight assembly or attempting to reseal the existing unit.
  • Estimated Cost to Fix: $100 - $500 per headlight
  • Recalls: None Found

Interior

• HVAC Actuator Failure
  • Description/Symptoms: Clicking or whirring noises coming from behind the dashboard, and/or inconsistent temperature control (e.g., one side blowing cold air while the other blows hot). The actuators control the blend doors that regulate airflow and temperature.
  • Solution: Replacement of the faulty HVAC actuator.
  • Estimated Cost to Fix: $200 - $500+
  • Recalls: None Found

Summary The 2004 Toyota Prius, while revolutionary for its time, has several common issues that potential buyers should be aware of. The most significant issues revolve around the hybrid battery, transaxle, and inverter, which can be very costly to repair or replace. Other issues, such as combination meter failure and HVAC actuator problems, are less severe but can still be inconvenient. Overall, prospective owners should factor in the potential for these repairs when considering purchasing a used 2004 Prius.