Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
General Information: Notes
A large number of ECU controlled systems are used in the Prius. In general, the ECU controlled system is considered to be a very intricate system requiring a high level of technical knowledge and expert skill to troubleshoot. However, the fact is that if you proceed to inspect the circuits one by one, troubleshooting of these systems is not complex. If you have adequate understanding of the system and a basic knowledge of electricity, accurate diagnosis and necessary repair can be performed to locate and fix the problem. This information is designed through emphasis from the above standpoint to help service technicians perform accurate and effective troubleshooting, and is compiled for the following major ECU controlled systems.
The troubleshooting procedure and how to make use of it are described in the articles linked to the Troubleshooting table.
| System | See |
|---|---|
| Engine | SELF-DIAGNOSTICS |
| Hybrid Vehicle Control System | HYBRID VEHICLE CONTROL SYSTEMS |
| HV Battery Control System | HV BATTERY CONTROL SYSTEM |
| Anti-Lock Brake System With EBD & RBS | ANTI-LOCK |
| Electric Motor Power Steering | ELECTRIC MOTOR POWER STEERING - DIAGNOSTICS |
| Supplemental Restraint System | AIR BAG RESTRAINT SYSTEMS |
| Cruise Control System | CRUISE CONTROL SYSTEMS |
| Combination Meter System | COMBINATION METER SYSTEM - DIAGNOSTICS |
| Body Control System | BODY CONTROL SYSTEM |
| Driver Door Control System | DRIVER DOOR CONTROL SYSTEM - DIAGNOSTICS |
| Multiplex Communication System | MULTIPLEX COMMUNICATION SYSTEM - DIAGNOSTICS |
| Navigation System | NAVIGATION SYSTEM - DIAGNOSTICS |
| Air Conditioning System | AIR CONDITIONING SYSTEM - DIAGNOSTICS |
NO RELATED
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.