Power Assist Systems

Fail-safe Chart

~1min read
FAIL-SAFE CHART

If a problem occurs in the power steering system, the power steering assist will be stopped or the amount of power assist will be decreased to protect the system.

Power Steering System

Malfunction

Fail-safe Operation

  • Torque sensor (steering column assembly) malfunction
  • Power steering motor (steering column assembly) malfunction
  • Power steering ECU assembly malfunction

Power steering assist stops or assist amount is limited

  • Vehicle speed signal malfunction
  • Skid control ECU (brake actuator assembly) malfunction
  • History of power steering ECU assembly overheating
  • History of decrease in battery voltage (not malfunction)

Power steering assist is temporarily limited

HINT:

  • The amount of power assist may be decreased to prevent the motor and ECUs from overheating if the steering wheel is continuously turned when the vehicle is either stopped or being driven at a low speed, or if the steering wheel is kept at either full lock position for a long time. In such cases, the amount of power assist returns to normal when the steering wheel is not turned for approximately 10 minutes with the engine idling.
  • If the battery is not sufficiently charged or the voltage decreases temporarily, the amount of power assist will be reduced and the EPS warning light will come on. In such cases, the amount of power assist returns to normal when the battery voltage recovers.

Test yourself

A quick Toyota Venza quiz: every answer comes with an explanation and a link to the manual page.