Late models of Nissan vehicles equip an electronic throttle body (ETB), which is fully controlled by a vehicle computer. After you replace an ETB, you will need to have the computer relearn the position of the throttle plate to maintain the correct idle speed. Sometimes, other repairs such as a battery replacement and ETB clean-up may cause the idling to act up. This problem may turn on Service Engine Soon light (=check engine light) and store the trouble code P0507 – Idle speed control system RPM higher than expected. If you are in this situation, you need to perform this Nissan idle relearn procedure below.
https://www.1aauto.com/how-to-reprogram-your-new-throttle-body-02-06-nissan-altima/video/13155
STEP 1: ACCELERATOR PEDAL RELEASE POSITION LEARNING
1) Do not depress the accelerator pedal
2) Turn the key to the ON position for at least 2 seconds
3) Turn the key to the OFF position for 10 seconds
4) Turn the key to the ON position for 2 seconds
5) Turn the key to the OFF position for 10 seconds
STEP 2: THROTTLE VALVE CLOSE POSITION LEARNING
1) Do not depress the accelerator pedal
2) Turn the key to the ON position for 10 seconds
3) Turn the key to the OFF position and listen for the throttle body making a whining sound
STEP 3: IDLE AIR VOLUME LEARNING
1) Run the vehicle up the operating temperature with the vehicle in park, the steering wheel straightened, and the headlights and A/C and other electrical loads off
2) At idle, make sure the vehicle has more than 12.9 volts at the battery
3) Let the vehicle reach up to temp
4) Turn the vehicle off
5) Let the ignition be off for 10 seconds
6) Do not depress the accelerator pedal
7) Turn the key to the ON position and wait 3 seconds
8) Press the accelerator pedal five times in 5 seconds
9) Wait for 7 seconds
10) Check engine light should flash
11) Hold the accelerator pedal down for 20 seconds
12) Release the accelerator pedal within 3 seconds when the engine light stops blinking
13) Start the engine and let it idle
14) Rev the engine a couple of times
15) Confirm the engine returns to the correct idle (around 700 RPM in park for automatic transmission)
16) Confirm there is no check engine light
The procedure is kind of tricky. The timing is critical. A stopwatch may help you perform the procedure with precise timing. Before the procedure, Service Engine Soon light needs to be cleared by disconnecting a battery cable for at least 30 seconds.
The procedure is necessary after replacing an ETB, disconnecting a batter, and so on. The idling starts acting up all of a sudden, something else may be the cause of the problem. So, if Service Engine Soon light is on, it is important to scan the computer, read and take notes of all codes. You might as well perform and see if it will fix the problem because the procedure doesn’t require any special tools. But if the same symptom exists or comes back, you can start diagnosing based on the codes on the notes you take before the procedure.