Civic CX Hatchback L4-1590cc 1.6L SOHC MFI (1997)
Idle Speed: Technical Service Bulletins
Engine Controls - Idle Speed Inspection With PGM Tester
03-016
May 19, 2006
Applies To:
1998-02 Accord -ALL
1996-00 Civic -ALL
1997-01 CR-V - ALL
1997-01 Prelude - ALL
*1999-04 Odyssey - ALL*
Inspecting Idle Speed With the PGM Tester or Honda Diagnostic System
(Supersedes 03-016, dated March 25, 2003, to update the information marked by asterisks)
BACKGROUND
The ECM/PCM controls the vehicle's idle speed with the idle air control (IAC) valve. The IAC valve and the air bleed screw (idle adjusting screw) work
together to allow the proper amount of air into the intake manifold when the throttle valve is closed (the accelerator pedal is released).
The ECM/PCM "learns" to work the IAC valve based on the total amount of air entering the intake manifold. Air can enter the intake manifold from
several sources, including the air bleed screw, but only the air bleed screw is adjustable. If any changes are made that alter this airflow, specifically with
the air bleed screw, the ECM/PCM must learn new idle parameters.
When the air bleed screw is properly set, the ECM/PCM controls the engine's idle speed seamlessly. But when the air bleed screw is not properly set,
either of these symptoms may be present:
^
Idle speed dips and then quickly recovers.
^
Engine stalls intermittently when it is just "off-idle." Here are the criteria for this symptom:
-
The accelerator pedal is released but the driver's right foot rests over the pedal, causing just enough pressure for the ECM/PCM to detect an
input, yet there is little or no throttle valve opening (the throttle valve is either not allowing any airflow or it is opened so slightly that more air
supply is needed).
-
The engine speed is about 1,250 rpm or less.
-
The lockup clutch (A/T models) or the clutch (M/T models) is disengaged.
-
All during this time, the driver's foot does not move and stays resting over the accelerator pedal.
-
The air bleed screw is not set properly and does not allow enough airflow.
-
The amount of "air leakage" into the intake manifold is very low. (The normal amount of air let into the intake manifold by sources other than the
IAC valve, the air bleed screw, and normal operation of the throttle body can vary slightly from vehicle to vehicle.)
NOTE:
"Air leakage" cannot be easily checked. If the first four criteria are met when the vehicle stalls, you can assume the last two criteria are met as
well.
CORRECTIVE ACTION
L4 Models and 1999-00 Odyssey: Inspect the idle speed with the PGM Tester or Honda Diagnostic System (HDS) (see INSPECTION PROCEDURE
A).
V6 Models except 1999-00 Odyssey: Inspect the idle speed with the PGM Tester or HDS, and clean out the throttle body if needed (see INSPECTION
PROCEDURE B).
PARTS INFORMATION
Throttle Body Gasket (use only if needed): Refer to the parts catalog.
TOOL INFORMATION
