Nissan Versa Sedan Service ManualEngine » Engine control system (EC)
Idle air volume learning
Idle air volume learning
Description
Idle Air Volume Learning is a function of ECM to learn the idle air volume that keeps each engine idle speed within the specific range. It must be performed under any of the following conditions:
- Each time electric throttle control actuator or ECM is replaced.
- Idle speed or ignition timing is out of specification.
Work Procedure
1.PRECONDITIONING
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 100C (158 212F)
- Selector lever: P or N (A/T or CVT), Neutral (M/T)
- Electric load switch: OFF (Air conditioner, headlamp, rear window defogger)
- For vehicles equipped with daytime light systems, perform one of the following procedures before starting engine not to illuminate headlamps.
- Apply parking brake
- Set lighting switch to the 1st position
- Steering wheel: Neutral (Straightahead position) position
- Vehicle speed: Stopped
- Transmission: Warmedup
- A/T or CVT models
- With CONSULT: Drive vehicle until "FLUID TEMP SE" in "DATA MONITOR" mode of "TRANSMISSION" system indicates less than 0.9 V.
- Without CONSULT: Drive vehicle for 10 minutes.
- M/T models
- Drive vehicle for 10 minutes.
Do you have CONSULT?
YES >> GO TO 2.
NO >> GO TO 3.
2.IDLE AIR VOLUME LEARNING
With CONSULT
- Perform ACCELERATOR PEDAL RELEASED POSITION LEARNING.
- Perform THROTTLE VALVE CLOSED POSITION LEARNING.
- Start engine and warm it up to normal operating temperature.
- Select "IDLE AIR VOL LEARN" in "WORK SUPPORT" mode with CONSULT.
- Touch "START" and wait 20 seconds.
Is "CMPLT" displayed on CONSULT screen?
YES >> GO TO 4.
NO >> GO TO 5.
3.IDLE AIR VOLUME LEARNING
Without CONSULT
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.
- Perform ACCELERATOR PEDAL RELEASED POSITION LEARNING.
- Perform THROTTLE VALVE CLOSED POSITION LEARNING.
- Start engine and warm it up to normal operating temperature.
- Turn ignition switch OFF and wait at least 10 seconds.
- Confirm that accelerator pedal is fully released, turn ignition switch ON and wait 3 seconds.
- Repeat the following procedure quickly five times within 5 seconds.
Fully depress the accelerator pedal.
Fully release the accelerator pedal.
- Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 20 seconds until the MIL stops blinking and turned ON.
- Fully release the accelerator pedal within 3 seconds after the MIL turned ON.
- Start engine and let it idle.
- Wait 20 seconds.
>> GO TO 4.
4.CHECK IDLE SPEED AND IGNITION TIMING
Rev up the engine two or three times and make sure that idle speed and ignition timing are within the specifications.
Is the inspection result normal?
YES >> INSPECTION END
NO >> GO TO 5.
5.DETECT MALFUNCTIONING PART
Check the following
- Check that throttle valve is fully closed.
- Check PCV valve operation.
- Check that downstream of throttle valve is free from air leakage.
Is the inspection result normal?
YES >> GO TO 6.
NO >> Repair or replace malfunctioning part.
6.DETECT MALFUNCTIONING PART
Engine component parts and their installation condition are questionable. Check and eliminate the cause of the incident.
It is useful to perform "TROUBLE DIAGNOSIS SPECIFICATION VALUE". 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.
>> INSPECTION END