Idle Air Volume Learning
DESCRIPTION
âIdle Air Volume Learningâ is an operation to learn the idle air volume
that keeps each engine within the specific range. It must be
performed under any of the following conditions:
-Each time IACV-AAC valve, throttle body or ECM is replaced.
-Idle speed or ignition timing is out of specification.
PRE-CONDITIONING
Before performing âIdle Air Volume Learningâ, make sure that all of
the following conditions are satisfied.
Learning will be cancelled if any of the following conditions are
missed for even a moment.
- Battery voltage: More than 12.9V (At idle)
- Engine coolant temperature: 70 - 95?C (158 - 203?F)
- PNP switch: ON
- Electric load switch: OFF
(Air conditioner, headlamp, rear window defogger)
On vehicles equipped with daytime light systems, if the parking
brake is applied before the engine is started the headlamp
will not be illuminated.
- Cooling fan motor: Not operating
- Steering wheel: Neutral (Straight-ahead position)
- Vehicle speed: Stopped
- Transmission: Warmed-up
For A/T models with CONSULT-II, drive vehicle until âFLUID
TEMP SEâ in âDATA MONITORâ mode of âA/Tâ system indicates
less than 0.9V.
For A/T models without CONSULT-II and M/T models, drive
vehicle for 10 minutes.
OPERATION PROCEDURE
Without CONSULT-II
1. Turn ignition switch âONâ and wait at least 1 second.
2. Turn ignition switch âOFFâ and wait at least 10 seconds.
3. Start engine and warm it up to normal operating temperature.
4. Check that all items listed under the topic âPRECONDITIONINGâ,
EC-83, are in good order.
5. Turn ignition switch âOFFâ and wait at least 10 seconds.
6. Start the engine and let it idle for at least 30 seconds.
7. Disconnect throttle position sensor harness connector (<wbr>brown),
then reconnect it within 5 seconds.
8. Wait 20 seconds.
9. Make sure that idle speed is within specifications. If not, the
result will be incomplete. In this case, find the cause of the
problem by referring to the NOTE below.
10. Rev up the engine two or three times. Make sure that idle
speed and ignition timing are within specifications.
NOTE:
If idle air volume learning cannot be performed successfully,
proceed as follows:
1) Check that throttle valve is fully closed.
2) Check PCV valve operation.
3) Check that downstream of throttle valve is free from air
leakage.
4) Adjust closed throttle position <wbr>switch and reset memory.
(Refer to Basic Inspection, EC-127.)
5) When the above three items check out OK, engine component
parts and their installation condition are questionable.
Check and eliminate the cause of the problem.
It is useful to perform âTROUBLE DIAGNOSIS SPECIFICATION
VALUEâ, EC-163.
6) If any of the following conditions occur after the engine
has started, eliminate the cause of the problem and perform
âIdle air volume learningâ all over again:
- Engine stalls.
- Erroneous idle.
- Blown fuses related to the IACV-AAC valve system.