Description
ECM has the memory function of the DTC memory, the air-fuel ratio feedback compensation value memory, the Idle Air Volume Learning value memory, etc. even when the ignition switch is turned OFF.

DTC DETECTION LOGIC
| DTC No. | Trouble diagnosis | DTC detecting condition | Possible cause |
|
P0603 |
ECM BACK UP/CIRCUIT (ECM power supply circuit) | ECM back-up RAM system does not function properly. |
|
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure before conducting the next test.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
Is 1st trip DTC detected?
YES >> Go to EC, "Diagnosis Procedure".
NO >> INSPECTION END
1.INSPECTION START
Is the 1st trip DTC P0603 displayed again?
YES >> GO TO 2.
NO >> INSPECTION END
2.REPLACE ECM
>> INSPECTION END
Engine protection control at low engine oil pressure
Engine protection control at low engine oil pressure : system diagram
Engine protection control at low engine
oil pressure : system description
INPUT/OUTPUT SIGNAL CHART
Sensor
Input signal to ECM
ECM function
Actuator
Engine oil pressure sensor
Engine pressure
...
Steering wheel
Inspection
CHECKING CONDITION OF INSTALLATION
Check installation conditions of steering gear assembly, front
suspension assembly, axle and steering column
assembly.
Check if movement exists when steering wheel is moved up and down, to
the left and right and to the axial
direction.
...