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".
P0139 HO2S2
DTC Logic
DTC DETECTION LOGIC
The heated oxygen sensor 2 has a much longer switching time
between rich and lean than the air fuel ratio (A/F) sensor 1. The oxygen
storage capacity of the three way catalyst 1 causes the longer
switching time. To judge the malfunctions of heated oxygen sensor
2, ...
Symptom diagnosis
Squeak and rattle trouble diagnoses
Work Flow
CUSTOMER INTERVIEW
Interview the customer if possible, to determine the conditions that exist
when the noise occurs. Use the Diagnostic
Worksheet during the interview to document the facts and conditions when the
noise occurs and any
custom ...
Symptom diagnosis
The eco mode indicator lamp does not turn on
Description
The ECO mode indicator lamp does not turn ON when the ECO mode switch is
operated.
Diagnosis Procedure
1.Perform combination meter on board diagnosis
Perform combination meter on board diagnosis. Refer to MWI-16, "Description" ...