Nissan Repair Questions? Ask a Mechanic for Answers ASAP
Hello, my name is XXXXX XXXXX I am here to assist you
Can you fill me in on what you are trying to do/fix?
vehicle failed emissions & vacuum cut valve bypass valve code came up
Can you tell me what the code number is?
There are several vacuum valves and I want to identify the correct part by the code.
Thanks...let me look that up.
Ok, here is a thread that is one of several that relate to this code. Unfortunately, most of the time the problem is nto the valve itself.
I will give you some info on the valve but you may buy and replace it and still have the problem
i considered the harness might be the problem also, but what someone told me was the idle control valve also known as the vacuum cut valve buy pass valve looked ruff & possibly missing a vacuum line
Here is a picture of the valve and its location.
The idle air control valve has nothing to do with code P1490. This code is an evaporative emissions code and relates to the circuit that operates the VCV valve that I sent you a picture of (not the clearest...sorry)
Here is a picture from my parts supplier:
You could replace this first but be aware that there are many instances of burnt wiring as well as damaged ECM's. I have to believe that the source of the problem is in the valve itself but there can be consequential damage in wiring and ECM.
i have had problems with the ECM in the passed so thats another possibility but i will start with the code problems first
Yes, it is unfortunate but Nissan Altimas have had ECM trouble. I would replace this valve, inspect the wiring to make sure it hasn't melted, clear codes and allow them to return prior to any further action.
Alan I appreciate all your help . many thanks & have a good day/night