Idle Air Volume Learning

DESCRIPTION
"Idle Air Volume Learning" 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 "Idle Air Volume Learning", 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 12.9 V (At idle)
- Engine coolant temperature: 70 - 99° C (158 - 210° F)
- PNP switch: ON
- Electric load switch: OFF
(Air conditioner, headlamp, rear window defogger)
On vehicles equipped with daytime running light Systems, set lighting switch to the 1st position to light only small lamps.
- Cooling fan motor: Not operating
- Steering wheel: Neutral (Straight-ahead position)
- Vehicle speed: Stopped

OPERATION PROCEDURE










With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Check that all items listed under the topic "PRE-CONDITIONING" (previously mentioned) are in good order.
3. Turn ignition switch "OFF" and wait at least 10 seconds.
4. Start the engine and let it idle for at least 30 seconds.
5. Select "IDLE AIR VOL LEARN" in "ACTIVE TEST" mode.
6. Touch "START' and wait 20 seconds.
7. Make sure that "CMPLT" is displayed on CONSULT-II screen. If "INCMP" is displayed, "Idle Air Volume Learning" will not be carried out successfully. In this case, find the cause of the problem by referring to the NOTE below.
8. Rev up the engine two or three times. Make sure that idle speed and ignition timing are within specifications.

ITEM SPECIFICATION
Idle speed M/T: 625 ± 50 rpm
A/T: 700 ± 50 rpm (in "P" or "N" position)
Ignition timing M/T: 15° ± 2° BTDC
A/T: 15° ± 2° BTDC (in "P" or "N" position)




Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Check that all items listed under the topic "PRE-CONDITIONING" (previously mentioned) are in good order.
3. Turn ignition switch "OFF" and wait at least 10 seconds.
4. Start the engine and let it idle for at least 30 seconds.
5. Disconnect throttle position sensor harness connector (brown), then reconnect it within 5 seconds.
6. Wait 20 seconds.
7. 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.
8. Rev up the engine two or three times. Make sure that idle speed and ignition timing are within specifications.

ITEM SPECIFICATION
Idle speed M/T: 625 ± 50 rpm
A/T: 700 ± 50 rpm (in "P" or "N" position)
Ignition timing M/T: 15° ± 2° BTDC
A/T: 15° ± 2° BTDC (in "P" or "N" position)

NOTE:
If idle air volume learning cannot be performed successfully,
proceed as follows:
1. Check that throttle valve is fully closed.
2. Check that downstream of throttle valve is free from air leakage.
3. Adjust closed throttle position switch and reset memory. (Refer to Basic Inspection.)
4. 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.
5. If any of the following conditions occur after the engine has started, eliminate the cause of the problem and perform "Idle air volume learning" all over again:
- Engine stalls.
- Erroneous idle.
- Blown fuses related to the IACV-AAC valve system.