No idle after Idle Control Valve Change

[BlueL82]

Replaced the idle control valve on my 02 Pathfinder. Before, it would stumble in idle and periodically die, with the code for a malfunctioning idle control valve. Now, it doesn’t idle at all with a new valve. How do I reset the idle? I feel like I should reset the idle through the cars computer before I start fiddling with the physical idle control screw.

[mdmellott]

You have to perform the Idle Air Volume Learning procedure found in the factory service manual on page EC-71.https://www.nicoclub.com/service-manual ... 002/ec.pdf but you should first check, and if necessary adjust, your throttle position sensor. That process can be found on page EC-122. There are two harness connectors attached to the TPS. To check the continuity specification for the TPS, you will be disconnecting the lower grey connector. To deal with the IACV relearn procedure, you will be disconnecting and reconnecting the upper brown connector in the process during the procedure. For the relearn procedure, there are preconditions that must be met before the procedure. Those preconditions are specified in the service manual as well. The relearn procedure is as follows. Read through the complete description in the service manual to better understand all of this and warm up the engine and transmission before you proceed.
1. Turn ignition switch “ON” and wait at least 1 second.
2. Turn ignition switch “OFF” and wait at least 10 seconds.
3. Start engine and warm it up to normal operating temperature.
4. Check that all items listed under the topic “PRE-CONDITIONING”
(previously mentioned) are in good order.
5. Turn ignition switch “OFF” and wait at least 10 seconds.
6. Start the engine and let it idle for at least 30 seconds.
7. Disconnect throttle position sensor harness connector (brown),
then reconnect it within 5 seconds.
8. Wait 20 seconds.
9. Make sure that idle speed is within specifications. If not, the
result will be incomplete. In this case, find the cause of the
incident by referring to the NOTE below.
10. Rev up the engine two or three times. Make sure that idle
speed and ignition timing are within specifications.

NOTE:
If idle air volume learning cannot be performed successfully,
proceed as follows:
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) Adjust closed throttle position switch and reset memory.
(Refer to Basic Inspection, EC-117.)
5) When the above four items check out OK, 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
VALVE”, EC-150.
6) 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.
* Blown fuses related to the IACV-AAC valve system.

[mdmellott]

... before I start fiddling with the physical idle control screw.

I should make one more note regarding your post. If you are referring to the stopper screw on the throttle body that adjusts the valve inside the throttle body; That screw was preset at the factory and marked with tamper detection paint when the throttle body was built. That screw is not for adjusting the idle and should never be readjusted unless there was physical damage done to the throttle body drum contact point to the stopper screw or the throttle body was rebuilt. The pinch point between the stopper screw and drum contact point is where you will be inserting a feeler gauge (.05mm and .15mm) when the TPS is adjusted. You will compound your idle issues if you reset the factory set valve position in the throttle body.

[BlueL82]

I tried the idle air volume reset, however it’s difficult since the car can’t idle. I’ve tried moving the tps and got it to crank but it does right away. this is a shade tree job, I don’t have access to a feeler gauge. Currently warming up the engine with my foot keeping it from dying to get it to operating temp to reset the tps.I will let you know, thank you for the help.

[BlueL82]

I just did the tmps reset steps 6 and 7, 20 times, does not idle. Lost at what to do.

[mdmellott]

You cannot adjust the TPS without feeler gauges and a multi-meter to check for continuity and adjust according to the specifications in the service manual. You said you do not have feeler gauges. Do you have a multi-meter? To reset the TPS idle position memory without adjusting the throttle position switch closed position in the first steps of the procedure, accomplishes nothing. You need to have the right tools to complete this. As noted in the IACV relearn procedure, there may be other components causing your idle issue. Vacuum leaks are the most common. From what you have described, it's possible the IACV was never the issue to begin with and replacing it has made the issue worse because there is no way to perform the relearn procedure without all the other effecting parts being correct.

[mdmellott]

Check the IACV you removed with a multi-meter. Measure the resistance across terminals 1 and 2, 2 and 3, 4 and 5, 5 and 6. The resistance of a good valve should be approximately 20 to 24 ohms across each pair. Was the condition of the valve pintle dry, wet, or oily when you removed it? Typically a used one removed may be blackened a bit but should be dry.

[BlueL82]

My “new” control valve ended up being junk. Thank you for the help though.