Check the following item when performing the trouble diagnosis.
Check any possible causes by interviewing the symptom and it′s condition from the customer if any malfunction, such as EPS warning lamp is turned ON, occurs.
Check if air pressure and size of tires are proper, the specified part is used for the steering wheel, and control unit is genuine part.
Check if the connection of steering column assembly and steering gear assembly is proper (there is not looseness of mounting bolts, damage of rods, boots or sealants, and leakage of grease, etc.).
Check if the wheel alignment is adjusted properly.
Check if there is any damage or modification to suspension or body resulting in increased weight or altered ground clearance.
Check if installation conditions of each link and suspension are proper.
Check if the battery voltage is proper.
Check connection conditions of each connector are proper.
Before connecting or disconnecting the EPS control unit harness connector, turn ignition switch “OFF” and disconnect battery ground cable. Because battery voltage is applied to EPS control unit even if ignition switch is turned “OFF”.
During quick steering, rasping noise may be heard from around the steering wheel. This is not a malfunction.
The noise is an operating noise of the EPS system under normal conditions. If the rasping noise occurs during slow steering, this may not be an operating noise of the system. In this case, it is necessary to find out the location of the noise and repair, if necessary.
Preparation
Commercial Service Tools

Precaution for Supplemental Restraint System (SRS) "AIR BAG"
and "SEAT BELT PRE-TENSIONER"Strg branch line circuit
Diagnosis procedure
1.Check connector
Turn the ignition switch off.
Disconnect the battery cable from the negative terminal.
Check the terminals and connectors of the steering angle sensor for
damage, bend and loose connection
(unit side and connector side).
Is the inspection result ...
Service data and specifications (SDS)
Service Data and Specification (SDS)
COMPRESSOR
OIL
REFRIGERANT
...
Malfunction indicator lamp
Component Function Check
1.CHECK MIL FUNCTION
Turn ignition switch ON.
Check that MIL lights up.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Proceed to EC-467, "Diagnosis Procedure".
Diagnosis Procedure
1.CHECK DTC WITH ECM
Check that DTC UXXXX i ...