How to Troubleshoot the Koyo EPS

Like so much else, the EPS is computer-based.

Koyo Seiko, also known as Koyo, pioneered the production of electric power-steering systems in Japan in 1988. Koyo supplies the automotive needs of Toyota, and also General Motors Co.'s Saturn Vue and Ion. Koyo's EPS units are speed-sensitive, featuring integrated torque sensors, and are said to produce a bit of fuel savings. "There are five different calibrations for the steering," says a GM spokesperson, "which correspond to the wheel and tire combinations offered on the sedan and coupe." Additionally, there are three more calibrations available. Begin troubleshooting the Koyo EPS by checking and verifying those calibrations

Things You'll Need

• DTC reader

Instructions

1. Turn on the vehicle. The EPS indicator comes on with the ignition switch, then goes off when the engine starts under normal operation.

2. Note the DTC or Diagnostic Trouble Code. If the EPS indicator light comes on after ignition, that indicates an error, and the EPS control unit memorizes the DTC. The EPS indicator often stays on until the vehicle is turned off.

3. Combine the DTC with known circumstances when the EPS indicated a problem to more effectively diagnose the individual issue.

References

• FastFieros.com: EPS=Electric Power Steering
• HondaFitJazz.com: How to Troubleshoot the EPS
• Koyo USA: Corporate Overview

Resources

• Wards Auto World: Koyo Ships EPS