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Jay
Jay, Nissan Technician
Category: Nissan
Satisfied Customers: 19301
Experience:  20+yrs experience with Nissan & Infiniti Trained & Certified.Currently still working for Dealer
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Ive got a 96 nissan pickup 2wd with 2.4 4 cylinder. I have ...

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Ive got a 96 nissan pickup 2wd with 2.4 4 cylinder. I have a check engine light so used a OBD 2 reader on it and discovered i had alot of codes. I uderstand that one problem could set off several codes. these are the codes I got. P505, P1441, P0135, P0446, P1130, P1105, P1400. I am on a tight budget and cant afford a mechanic. I can do it myself if I know what to replace. I dont want to have to guess. That usually takes more time and more money. I know alot about the "old school" stuff, but all these sesors and valves get me confused. If you would please lead me in the right direction i will certainly appreciate it.
Hello and thank you for using JustAnswer.com

Thats allot of codes you got there. This may require allot of diag. Let me give you the list on what codes you have, then move on from there.

P0505 IACV ( Idle Air Control Valve)
P1441 VC/ V Bypass V ( Vacuum Cut Bypass Valve ) Part of the Evap system.
P0135 Front O2 sensor heater
P0446 Vent Control Valve - Also part of Evap system
P1105 Map Boro Switch ( Manifold Absolute Pressure switch solenoid )
P1400 Egr Solenoid

As you can see, almost all of these codes are of different systems except for the 2 evap codes. Each code requires diagnostic steps to find the problem. The steps will require special tools as well. Some of these codes may be tough to diagnosis over the net.

Let me know what direction you want to take. Thanks Jay
Customer: replied 8 years ago.
I want to focus on the ones that affect my fuel economy so i would want the diagnoses of those that would pretain more to the fuel economy. the truck idles real low and hesitates when you step on the gas. so lets fix that problem first. then what ever codes are on after that we will direct the attention to.
thanks for taking the time out of your scedule to look at my questions. Customer
Well the Evap codes, you leave them for now. The P0505 IAC valve should be checked. Do you have a volt meter to perform voltage tests and wiring signal check?
Customer: replied 8 years ago.
yes i have a voltmeter. how do i need to check it?
Sorry it took so long for me to get back to you. Glad you have a meter. Here is the diagnostic steps for PO505 code. Here is the first image. I will attach component check also, Just have to reboot. Program crashed.graphic
Jay and 2 other Nissan Specialists are ready to help you
Here is the component check.graphic
Jay and 2 other Nissan Specialists are ready to help you
Customer: replied 8 years ago.
what does it mean when it shows the ecm connector? thanks for the diagram. but i need to know what it means about the ecm connector. is this where i put in my OBD 2 READER?
Yes, you are to ohm the wire from the IAC to the Ecm to make sure wire is good. here is the connector pin lay out on the ecm. You need to tap into pin 101, My programed crashed again, Be right back again.. got to reboot
Customer: replied 8 years ago.
also it doesnt say what the readings should be. do you know? when the key switch in on does the engine need to be running?
For picture A, Key on, Engine off. For picture B, Key off.

Sorry about the delay, having some computer problems tonight. Here is the ECM connector image.graphic
Customer: replied 8 years ago.
I got a reading of 10.4 ohms on the AIV. so I dont think its that. So i have to disconnect the ecm and then probe the connector?
As long as the spring is good & the plunger is free. Yes the valve does sound like it could be good. You need to check voltages and wire continuity next.
Customer: replied 8 years ago.
thanks. how do i check the spring and plunger? what should the voltage be?
Sorry it took me so long to get back to you.

Pin 2 on the IAV should be 12volts. To check the spring and plunger, you have to listen to it's operation. The idle screw should be free and able to be turned also.
Customer: replied 8 years ago.
OK I HAVE A PROBLEM? WHEN I FIRS CRANK MY TRUCK IT NEARLY ACTS LIKE ITS GOING TO DIE. AND WHEN I AM CHANGING GEARS IT HESITATES TO ACCELERATE. IS THERE ANYTHING YOU THINK I NEED TO REPLACE TO FIX THAT. I AM AFFRAID THAT I MAY HAVE TO REPLACE MY MASS AIR FLOW SENSOR WHICH RUN A LITTLE OVER $400 DOLLARS. THATS HARD TO SPEND ON A TRUCK THAT AINT EVEN WORTH $2500.
It's possible, If you can read the air fuel mixture, it would tell me how the MAF sensor is working. It should be around 100%. If it's at 135% your to lean, if you 79% your rich.

You also have 2 solenoid codes, EGR & Map Boro, I said this wasn't going to be easy, with that many codes. These other 2 systems may be adding to your problem & also the O2 sensor code you have.

I understand it's frustrating. With this many codes, all the systems involved, has to be broken down and diag'd separately, to correct each problem. Then if all that doesn't fix it, you have to double check the basics and sensor reading.
Customer: replied 8 years ago.
THE O2 SENSOR IS CONFUSING ME. I PUT A BRAND NEW ONE ON BUT NOTHING CHANGED SO I ASSUMED IT WAS SOMETING ELSE MAKING THE O2 MALFUNCTION. HOW DO I READ THE AIR/FUEL MIXTURE?
To read the Air/Fuel mixture you will need a scan tool that has that capability. If your Alfa is max'd out lean or rich, it will put the engine into some kind of fail safe. When in fail safe, the o2 sensor will not read properly at idle.
Customer: replied 8 years ago.
How do I know it went in a fail safe mode? that sounds like what happened. it runs but not real good.
It's hard to tell. I know with the Nissan scan tool, when I am looking at all the readings, I could tell something is not right. At that point I have to find the problem to bring sensors back to spec.