HOW TO: Learning Procedures

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Pwnin O'Brien
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HOW TO: Learning Procedures

Postby Pwnin O'Brien » Sun Aug 23, 2009 7:53 pm

******************************I AM CURRENTLY UPDATING THIS THREAD TO REFLECT THE PROPER RELEARNING PROCEDURES FOR ALL PATHFINDER/QX4 YEARS.******************************

The following learning procedures will allow your ECU to re-learn important sensor data. This data can be lost if the ECU has been reset or if the vehicle has been inactive for extended periods of time with a dead battery. All of the following procedures are fairly time sensitive and any discrepancies in timing can produce a DTC and the SERVICE ENGINE SOON lamp will illuminate. It is recommended that you perform the following procedures using an accurate counting method (one one-thousand, two one-thousand, etc..) if a timer or stopwatch is inaccessible.

It is recommended that the procedures be completed in the following order. If an error occurs, you should reset the ECU and start the following procedures over. The following procedures can be completed on most (but not all) R50 and R51 models. Completion of any of the following procedures on a vehicle which does not warrant it will not produce any DTC's or damage the vehicle.

Please read all steps before beginning any procedure.

________________________________________________________ACCELERATOR PEDAL RELEASED POSITION LEARNING (2003 - 2004 Pathfinders + QX4's)"]________________________________________________________

Description:

“Accelerator Pedal Released Position Learning” is an operation to learn the fully released position of the accelerator pedal by monitoring the accelerator pedal position sensor output signal. It must be performed each time harness connector of accelerator pedal position sensor or ECM is disconnected.

Procedure:

1. Make sure that accelerator pedal is fully released.

2. Turn ignition switch “ON” (without starting vehicle) and wait at least 2 seconds.

3. Turn ignition switch “OFF” wait at least 10 seconds.

4. Turn ignition switch “ON” (without starting vehicle) and wait at least 2 seconds.

5. Turn ignition switch “OFF” wait at least 10 seconds.

________________________________________________________THROTTLE VALVE CLOSED POSITION LEARNING (2003 - 2004 Pathfinders / QX4's)"]________________________________________________________

Description:

“Throttle Valve Closed Position Learning” is an operation to learn the fully closed position of the throttle valve by monitorizing the throttle position sensor output signal. It must be performed each time harness connector of electric throttle control actuator or ECM is disconnected.

Procedure:

1. Make sure that accelerator pedal is fully released.

2. Turn ignition switch “ON” (without starting vehicle).

3. Turn ignition switch “OFF” wait at least 10 seconds.

Make sure that throttle valve moves during above 10 seconds by confirming the operating sound.

________________________________________________________IDLE AIR VOLUME LEARNING (2003 - 2004 Pathfinders / QX4's)"]________________________________________________________

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 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 12.9V (At idle) - Engine coolant temperature: 70 - 100°C (158 - 212°F)- PNP switch: ON- Electric load switch: OFF (Air conditioner, headlamp, rear window defogger)On vehicles equipped with daytime light systems, set lighting switch to the 1st position to light only small lamps.- Steering wheel: Neutral (Straight-ahead position)

Procedure:

1. Start engine and warm it up to normal operating temperature.

2. Check that all items listed under the topic “Preparation” (previously mentioned) are in good order.

3. Turn ignition switch “OFF” and wait at least 10 seconds.

4. Confirm that accelerator pedal is fully released, turn ignition switch “ON” (without starting vehicle) and wait 3 seconds.

5. Repeat the following procedure (5-a and 5-b) quickly five times within 5 seconds.

5-a. Fully depress the accelerator pedal.

5-b. Fully release the accelerator pedal.

6. Wait 7 seconds, fully depress the accelerator pedal and keep it for approximately 20 seconds until SERVICE ENGINE SOON stops blinking and turns ON.

7. Fully release the accelerator pedal within 3 seconds after SERVICE ENGINE SOON turned ON.

8. Start engine and let it idle.

9. Wait 20 seconds.

Image
(Timing diagram)

10. Rev up the engine two or three times and make sure that idle speed and ignition timing are within the specifications.

Image
(The above specifications apply to R50 model ONLY; R51 model has different specifications)

11. If idle speed and ignition timing are not within the above 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: (Perform only if Idle Air Volume Learning was unsuccessful)

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.

Good Luck!


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slickroger
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Re: HOW TO: Learning Procedures (Pwnin O'Brien)

Postby slickroger » Sun Aug 23, 2009 11:04 pm

should this procedure only be performed if the ECU has been reset?

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Pwnin O'Brien
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Re: HOW TO: Learning Procedures (slickroger)

Postby Pwnin O'Brien » Mon Aug 24, 2009 6:27 am

Each procedure description also tells you under what circumstances you would need to complete each individual procedure, outside of having the ECU reset. For example, if the accelerator pedal position sensor has been disconnected with the vehicle battery still connected then you would need to complete only the "Accelerator Pedal Released Position Learning." Otherwise, if the ECU is reset, then all of the procedures need to be completed.

Likewise, any of the procedures can be completed at any time without the ECU having been reset. So if you have an erroneous idle, then you can complete the "Idle Air Volume Learning" at any time to correct your idle specification.

Lars
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Re: HOW TO: Learning Procedures (Pwnin O'Brien)

Postby Lars » Mon Aug 24, 2009 6:41 am

Great post! One question though... what years does this apply to?

corymoto
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Re: HOW TO: Learning Procedures (Lars) What Years?

Postby corymoto » Fri Dec 04, 2009 5:22 am

Excellent post, but what production years does it apply to? I have a 2001 QX4 with a rough idle after cleaning the MAF and throttle body, but I'm afraid I might mess something up if this how to is for a different year/engine.

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Pwnin O'Brien
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Re: HOW TO: Learning Procedures (Lars) What Years? (corymoto)

Postby Pwnin O'Brien » Fri Dec 04, 2009 5:39 am

corymoto wrote:Excellent post, but what production years does it apply to? I have a 2001 QX4 with a rough idle after cleaning the MAF and throttle body, but I'm afraid I might mess something up if this how to is for a different year/engine.
The Idle Air Volume Learning procedure for the '01 QX4 is actually completely different (and much easier than the one above). The procedure for your vehicle can be found in the FSM (more specifically 'Engine Control System.pdf') starting on page EC-57. The actual procedure (the procedure without CONSULT-II) begins on EC-58.

If you don't have 'Engine Control System.pdf' here is a link to it... http://www.nicoclub.com/FSM/QX...m.pdf

I've been meaning to modify this thread to reflect the procedures for each model year.

skulboep
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Re: HOW TO: Learning Procedures (Pwnin O'Brien)

Postby skulboep » Wed Feb 10, 2010 3:58 pm

I was installing a PAC audio steering wheel interface for my 2002 Pathy and turned the ignition to the "ACC" position w/ the car battery still connected (necessary to set up the unit). Afterwards the "Service Engine Soon" light appeared on my dash, presumably because a short occurred during installation (several wires from my harness were left unconnected at the time).

I am going to reset my ECU in an attempt to clear this light and then teach the ECU to re-learn the described data. Will these procedures work for a 2002 Pathfinder LE?

Thanks!


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Pwnin O'Brien
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Re: HOW TO: Learning Procedures (skulboep)

Postby Pwnin O'Brien » Wed Feb 10, 2010 4:20 pm

skulboep wrote:I was installing a PAC audio steering wheel interface for my 2002 Pathy and turned the ignition to the "ACC" position w/ the car battery still connected (necessary to set up the unit). Afterwards the "Service Engine Soon" light appeared on my dash, presumably because a short occurred during installation (several wires from my harness were left unconnected at the time).

I am going to reset my ECU in an attempt to clear this light and then teach the ECU to re-learn the described data. Will these procedures work for a 2002 Pathfinder LE?

Thanks!
For your 2002 Pathfinder you will only need to complete the Idle Air Volume Learning procedure. The Idle Air Volume Learning procedure above is the same process for your '02.

skulboep
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Car: 2002 Nissan Pathfinder LE

Re: HOW TO: Learning Procedures (Pwnin O'Brien)

Postby skulboep » Fri Mar 12, 2010 11:55 am

Pwnin please help!!!

I'm able to initiate the "Idle air volume learning" sequence without a problem. I pump the accelorator 5x, wait 7 secs and then depress and hold the accelorator. The "Service Engine Soon" lamp starts blinking after approx. 10 secs but just remains blinking. It never converts to being a solid ON.

I'm sure the vehicle meets all the necessary prerequsites (although I don't know what the "PNP" switch is) and I am pretty certain nothing else is wrong with the throttle or PCV valve.

My idle is REALLY screwed up and I need to fix this, it fluctuates between 1500 and 2100 rpm. Please help!

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04LEMASS
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-K&N Air Intake

Re: HOW TO: ECU Relearning Procedures

Postby 04LEMASS » Sat Jun 09, 2012 8:03 pm

what exactly is the "operating sound" of the thottle

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edogg27
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Re: HOW TO: ECU Relearning Procedures

Postby edogg27 » Sat Jun 23, 2012 11:21 am

My idle was about 1200 and i switched out the airbox to a k &n intake and it dropped to 950 so i did the idle volume air relearn and it droped to 750 and then next time i started it up it went back to 1000.


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