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. | CONSULT screen terms (Trouble diagnosis content) | DTC detecting condition | Possible cause |
P0506 | ISC SYSTEM (Idle air 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, performEC-140, "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-334, "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-485, "Removal and Installation".
Front bumper
Exploded view
Grommet
Front bumper side bracket (RH)
Front under cover
Front air spoiler
Front bumper reinforcement
Front energy absorber
Front fog lamp (RH) (if equipped)
Front bumper lower grille
Front bumper fascia finisher (RH)
(if equipped)
Front fog lamp finisher (R ...
Diagnosis system (ECM)
Diagnosis description : 1st trip detection
logic and two trip detection logic
When a malfunction is detected for the first time, 1st trip DTC and 1st trip
Freeze Frame data are stored in the
ECM memory. The MIL will not illuminate at this stage. <1st trip>
If the same malfunction is dete ...
P0172 Fuel injection system function
DTC Logic
DTC DETECTION LOGIC
With the Air/Fuel Mixture Ratio Self-Learning Control, the actual mixture
ratio can be brought closely to the
theoretical mixture ratio based on the mixture ratio feedback signal from the
A/F sensors 1. The ECM calculates
the necessary compensation to correct th ...