This 2004 Nissan Altima 2.5S came in with a high cold idle followed by a high and surging warm idle. A few of the things I noticed right away was a fairly new battery.
And a new starter assembly.
I wanted to take a look at the throttle body, so I removed the intake tube by loosening the clamp at the Mass Air Flow sensor.
Then the clamp at the throttle body.
I had to disconnect the vent tube to the valve cover and this hose that is the transmission vent hose. It is very important that this hose be put back in place when the intake tube is reinstalled.
I did not really want to see this. Notice the run marks left by throttle body cleaner being sprayed into the air horn. Also pay attention to the fact that some of the electronics are below the throttle plate. I do not have a Nissan Consult II scan tool so I needed to perform a manual relearn procedure for Idle Air Volume.
After many hours of trying every conceivable variation of the relearn procedure I decided the throttle body had to be replaced. I wanted to document the relearn procedure step by step so I started again with the factory procedure as given by Mitchell. It did not work, so I modified it, to what did work for me. Along with some general clarification. This is quite lengthy so please bear with me.
First of all, IF the battery, ECM or throttle body has been disconnected these conditions may all have to be performed to stabilize the idle and remove the code P0507. If any other codes are present this procedure may not work. If other codes are present diagnose and repair those problems first. Then perform this procedure to clear out the single P0507 code.
Accelerator Pedal Released Position Learning Procedure
This procedure allows the ECM to learn the fully released position of the APP sensor (Accelerator Pedal Position). It must be performed if the APP sensor or the ECM harnesses have been disconnected.
1. Ensure the accelerator pedal is fully released.
2. Turn the ignition on and wait at least 2 seconds.
3. Turn the ignition off and wait at least 10 seconds.
4. Turn the ignition on and wait at least 2 seconds.
5. Turn the ignition off and wait at least 10 seconds.
There is nothing else stated, so my assumption was to start the engine.
Throttle Valve Closed Position Learning
This procedure allow the ECM to learn the throttle plate closed position by monitoring the TPS output signal. It must be performed after either the throttle body or ECM harness has been disconnected.
1. Ensure that the accelerator pedal is fully released.
2. Turn the ignition switch on.
3. Turn the ignition off and wait at least 10 seconds. Confirm that the
throttle body plate moves by either observing or listening for the
movement during the 10 second wait period.
Again my assumption is to start the engine at this point.
Idle Air Volume Learning Procedure
1. Perform Accelerator Pedal Released Position and Throttle Valve
Closed Position relearning
2. Start and warm the engine to normal operating temperature (193
degrees F recommended).
3. The above relearning needs to be completed. The engine and
transmission need to be fully warmed up. There must not be any
problems with the APP sensor. It is best to use a clock with a
second function for timing.
4. Turn the ignition off and wait at least 10 seconds.
5. Make sure the accelerator pedal is fully released.
6. Turn the ignition on and wait 3 seconds.
7. Fully depress and fully release the accelerator 5 times within 5
seconds. Leaving the pedal in the released position.
8. Wait 7 seconds, then fully depress the accelerator pedal and keep
it held down for about 20 seconds. During this time the SES light
will start blinking.
9. Within 3 seconds of the light turning back on steady, fully release
the accelerator pedal. The factory information states that the next
step will be for the SES light to turn off. My findings were that the
light would not turn off and that the engine also needs to be started
within that 3 second window at the beginning of step 9.
10.With the engine running at 1000 rpm or less allow the engine to run
for at least 20 seconds. This is when the actual relearn is
happening. After the 20 second wait period, rev the engine to 3000
rpm two or three times and allow the engine to settle back down to
idle. Clear the code with a scan tool if needed and confirm that it
does not return. Idle and timing should now both be within
specifications. If not repeat the process.
11.If all criteria are not met the relearn will not work.
12.Here is the big issue, if the throttle body is not working properly or if
it has been cleaned and the engine will not idle below 1000 rpm, you
must create a condition under which the rpm will drop to 1000 or
If your warm idle speed is above 1000 rpm and it needs to be dropped to perform the Idle Air Volume Relearn, you must disconnect the wiring harness to no more than two fuel injectors. I disconnected the wiring to the number 1 and 4 injectors. I used long needle nosed pliers to do this. Number 1 in the next picture.
Now number four injector is disconnected. I fully warmed the engine and transmission before disconnecting the injectors. To my surprise the engine ran fairly well and dropped to about 800 rpm. I performed the IAVR procedure and it dropped even further. I then reconnected the injector harnesses and performed the IAVR again. Finally all is well again with this Nissan.
I used these pliers to release the injector connectors.
I had to switch to these to reconnect them. Yes, this is a medical tool but you can pick them up from flea markets.