Idle Air Volume Learning

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 of the following conditions:

- Each time electric throttle control actuator or ECM is replaced.
- Idle speed or ignition timing is out of specification.

Preparation

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 - 95 °C (158 - 212 °F)
- Selector lever position: P or N (A/T), Neutral (M/T)
- Electric load switch: OFF
(Air conditioner, headlamp)
On vehicles equipped with daytime light systems, if the parking brake is applied before the engine is started the headlamp will not be illuminated.
- Steering wheel: Neutral (Straight-ahead position)
- Vehicle speed: Stopped
- Transmission: Warmed-up

- A/T models

- With SDT: Drive vehicle until "ATF TEMP SE 1" in "Data list" mode of "A/T" system indicates less than 0.9 V.
- Without SDT: Drive vehicle for 10 minutes.

- M/T models: Drive vehicle for 10 minutes.

Operation Procedure

With SDT

1) Perform [Accelerator Pedal Released Position Learning] Testing and Inspection.
2) Perform [Throttle Valve Closed Position Learning] Throttle Valve Closed Position Learning.
3) Start engine and warm it up to normal operating temperature.
4) Check that all items listed under the topic PREPARATION (previously mentioned) are in good order.
5) Select "IDLE AIR VOL LEARN" in "Utility" mode.
6) Touch "START" and wait 20 seconds.
7) Make sure that "CMPLT" is displayed on SDT screen. If "CMPLT" is not displayed, Idle Air Volume Learning will not be carried out successfully. In this case, find the cause of the incident by referring to the DIAGNOSTIC PROCEDURE below.
8) Rev up the engine two or three times and make sure that idle speed and ignition timing are within the specifications. Refer to [Idle Speed and Ignition Timing Check] Idle Speed and Ignition Timing Check.






Without SDT

NOTE:

- It is better to count the time accurately with a clock.
- It is impossible to switch the diagnostic mode when an accelerator pedal position sensor circuit has a malfunction.

9) Perform [Accelerator Pedal Released Position Learning] Testing and Inspection.
10) Perform [Throttle Valve Closed Position Learning] Throttle Valve Closed Position Learning.
11) Start engine and warm it up to normal operating temperature.
12) Check that all items listed under the topic PREPARATION (previously mentioned) are in good order.
13) Turn ignition switch OFF and wait at least 10 seconds.
14) Confirm that accelerator pedal is fully released, turn ignition switch ON and wait 3 seconds.
15) Repeat the following procedure quickly 5 times within 5 seconds.
a) Fully depress the accelerator pedal.
b) Fully release the accelerator pedal.
16) Wait 7 seconds, fully depress the accelerator pedal for approx. 20 seconds until the MIL stops blinking and turns ON.
17) Fully release the accelerator pedal within 3 seconds after the MIL turns ON.
18) Start engine and let it idle.
19) Wait 20 seconds.





20) Rev up the engine two or three times and make sure that idle speed and ignition timing are within the specifications. Refer to [Idle Speed and Ignition Timing Check] Idle Speed and Ignition Timing Check.






21) If idle speed and ignition timing are not within the specification, Idle Air Volume Learning will not be carried out successfully. In this case, find the cause of the incident by referring to the DIAGNOSTIC PROCEDURE below.

Diagnostic Procedure

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) When the above three items check out OK, engine component parts and their installation condition are questionable. Check and eliminate the cause of the incident.
5) If any of the following conditions occur after the engine has started, eliminate the cause of the incident and perform Idle Air Volume Learning all over again:
- Engine stalls.
- Erroneous idle.