I decided to "tune-up" my X-Trail a little bit. I "recharged" my K&N air filter, vacuumed out the air filter housing, and cleaned my throttle body. Unfortunately, instead of getting better results, I now have rpm between 1400 and 1600. Before the tune-up, I was idling normally (750 rpm).
I have phoned the nearest Nissan dealership and I spoke to a tech. He told me that I have to bring my X-Trail in and have their scan tool diagnose the problem. He also said that I may have caused the ECM to lose it's ability to "idle air learn". When I cleaned my throttle body, I had to take it off of the intake manifold. But, there was a connection that I had to disconnect in order to make it easier to clean. I am going to assume that this is the "throttle position sensor".
Anyway, I put everything back together and there didn't seem to be a problem when I started my X-Trail. I had to put a few things back in the house, and when I came out I noticed that my idle was high. Not long after that, my CEL (check engine light) came on. I disconnected the battery for a good hour while I washed my X-Trail. When I reconnected the battery, the CEL didn't come back on, but the rpm are still high.
Has anyone else done this, and if so, what was your solution to solving the problem (s) before taking your X-Trail to the dealership?
Note
I have done a search, here, and nothing really pops up that pertains to the problem (s) that I am having.
According to the FSM, the No load* (in P or N position) idle speed is around 650 +/- 50 rpm. The idle speed is controlled by the ECU on most late model vehicles; there is no manual adjustment like they had on the old vehicles. If you need to bring the idle speed back to spec, there is a procedure called the "Idle Air Volume Learning" (IAVL) which is a function of ECU to learn the idle air volume that keeps the engine idle speed within the specific range. It must be performed after any of the following conditions:
• Each time the electric throttle control actuator or ECU is replaced.
• Each time the throttle body harness connectors are unplugged/replugged.
• Idle speed or ignition timing is out of specification.
• Check Engine Light (CEL) with P0507 trouble code and high/pulsating idle.
Disconnect the negative battery terminal for 30 seconds to reset the ECU. Do not perform the relearn procedure if the check engine light (CEL) is still on and codes related to the mass airflow sensor, manifold absolute pressure, or incorrect idle speed are found. If everything is in order, we can begin.
----------------------------------------------------------------------------------
TOOLS NEEDED: stopwatch or timer showing seconds.
ACCELERATOR PEDAL RELEASED POSITION LEARNING
Do not start engine in this procedure.
1. Make sure the accelerator pedal is fully released.
2. Turn ignition switch ON and wait at least 2 seconds.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Turn ignition switch ON and wait at least 2 seconds.
5. Turn ignition switch OFF and wait at least 10 seconds.
----------------------------------------------------------------------------------
THROTTLE VALVE CLOSED POSITION LEARNING
Do not start engine in this procedure.
1. Make sure the accelerator pedal is fully released.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Make sure throttle valve moves during above 10 seconds by confirming the operating sound.
-----------------------------------------------------------------------------------
IDLE AIR VOLUME LEARNING
1. First, bring the engine/transmission to normal operating temperature, 70-100°C or 158-212°F; do this by driving on the road for not less than 30 minutes; warming up the car in the garage doesn’t cut it! Next turn off all accessories such as the air conditioning, rear window defogger, radio, and heater blower to prevent a load on the engine which would cause erroneous positioning of the throttle plate. Finally, make sure the front wheels of the vehicle are in the neutral position pointing straight ahead. We are now ready to perform the required relearn procedure.
2. Selector lever: P or N (CVT), neutral (M/T), Battery voltage: More than 12.9V (At idle), engine coolant temperature: 70-100°C or (158-212°F), turn off all electrical powered stuff, wheels turned straight.
3. Shut off engine and wait at least 10 seconds.
4. With the foot off the brake pedal, turn ignition switch to the ON position(not START) or push ignition switch button to the ON position(two taps) and start the stopwatch at the same time.
5. When the stopwatch is at 3 seconds, press & release the accelerator pedal 5 times fully and quickly within 5 seconds.
6. Wait 7 seconds or more then fully press the accelerator pedal and hold for approximately 20 seconds or more until the CEL stops blinking and stays ON constantly.
(note: If the CEL never starts blinking, then something is not working and you'd better start over again).
7. Within 3 seconds after the CEL stays on constantly, release the accelerator pedal.
8. Immediately start the engine and let it idle. It may still likely be a high-rev/pulsating idle.
9. Let it run for no less then 20 seconds, then rev the engine a few times.
10. With the foot on the brake pedal, shift into Drive. Idle should now go down under 1000 rpm. Shift to Park or neutral again, and the car should find its regular idle speed. Operation will be normal except the CEL might still be on. It may disappear soon on its own, or you can do the following:
-----------------------------------------------------------------------------------
EASY RESET OF CHECK ENGINE LIGHT (CEL)
1. Turn the key OFF and wait at least 10 secondsis by far the best tool around for checking out CVT's, and
2. Turn the key ON (no ignition), wait 3 seconds, then press & release the accelerator pedal 5 times fully and quickly within 5 seconds.
3. Wait 10 seconds, then fully press the accelerator.
4. After about 12 seconds, CEL should go off then start blinking. As soon as it starts blinking, release the accelerator.
5. Wait 10 seconds, then fully press the accelerator.
6. Wait 10 seconds, then fully release the accelerator.
7. Turn the key to OFF, then immediately start the engine. The CEL should now be off.
-----------------------------------------------------------------------------------
(special note: If the IAVL fails to complete because of high idle due to other conditions, unplug one or more fuel injector harness connectors to bring down the idle speed.)
=============================================================================
Also If you have an Android phone, the CVTz50 app can also perform an IAVL. All you need to make it work is an ELM327 adaptor for under $20. The VeePeak VP11 is the best-cheapest one that gives you full function with CVTz50.
