Description
The ECM controls the engine idle speed to a specified level through the fine adjustment of the air, which is let into the intake manifold, by operating the electric throttle control actuator. The operating of the throttle valve is varied to allow for optimum control of the engine idling speed. The crankshaft position sensor (POS) detects the actual engine speed and sends a signal to the ECM.
The ECM controls the electric throttle control actuator so that the engine speed coincides with the target value memorized in the ECM. The target engine speed is the lowest speed at which the engine can operate steadily.
The optimum value stored in the ECM is determined by taking into consideration various engine conditions, such as during warming up, deceleration, and engine load (air conditioner, power steering and cooling fan operation, etc.).
DTC Logic
DTC DETECTION LOGIC
NOTE: If DTC P0506 is displayed with other DTC, first perform the trouble diagnosis for the other DTC.
DTC No. | Trouble diagnosis name | DTC detecting condition | Possible cause |
P0506 | ISC SYSTEM (Idle speed control system RPM lower than expected) | The idle speed is less than the target idle speed by 100 rpm or more. |
|
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure before conducting the next test.
If the target idle speed is out of the specified value, perform EC, "Work Procedure", before conducting DTC Confirmation Procedure.
TESTING CONDITION:
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
Is 1st trip DTC detected?
YES >> Proceed to EC, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis Procedure
1.CHECK INTAKE AIR LEAK
Is intake air leak detected?
YES >> Discover air leak location and repair.
NO >> Replace ECM. Refer to EC, "Removal and Installation".
Description The vehicle speed signal is sent to the combination meter from the "ABS actuator and electric unit (control unit)" by CAN communication line. The combination meter then sends a signal ...
Description The ECM controls the engine idle speed to a specified level through the fine adjustment of the air, which is let into the intake manifold, by operating the electric throttle control ac ...
A/T Fluid cooler
Cleaning
Whenever the A/T is repaired, overhauled, or replaced, the A/T fluid cooler
mounted in the radiator must be
inspected and cleaned.
Metal debris and friction material, if present, can become trapped in the A/T
fluid cooler. This debris can contaminate
the newly serviced A/T or, i ...
U0100 Lost communication (ECM A)
DTC Logic
DTC DETECTION LOGIC
DTC
Trouble diagnosis name
DTC detection condition
Possible causes
U0100
Lost Communication With
ECM/PCM "A"
When the ignition switch is ON,
TCM is unable to receive the
CAN communications signal
from ECM continuously for 2
...