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Discussion Starter #1
Hi,

I have a 2001 Pathfinder SE. My service engine light went on. My truck is off warranty and I would like to access the computer codes myself. An anyone tell me where the computer is on the Pathfinder? Also, is there a site that tells what each code means. I found one for the maxima if anyone is interested?

I checked my gas cap and it was on tight and the truck runs great. I was about 1/8 of a mile from a bolt of lightening that hit. It made a few car alarms go off and my truck was running. I have a feeling this might have set it off.
 

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The interface port is right near your left knee under the dash. It is the OBDII port, which is the same on ALL OBDII cars. I am not sure that you can ground the ecu to get codes like you could on OBDI. If you have a scan tool you could get the code and clear it. We get a lot of people who come in with "check engine" lights and it is a code for "small evap leak" which is 9/10 times a loose gas cap. It kinda sucks for those people because they basically have to pay us that hour for diagnostic time and it was just the gas cap. And you have to get the code cleared for the light to go out. Well hope this helps.
 

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Damn your shop charges an hour diag for code checking/clearing. Most times if the customer just want the light shut off and no further diag, we do it for free.
 
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My mechanix doesn't charge for clearing the light either. I'm sure the dealer would. So Nissan made it so I can't access the computer without a special tool. Too bad becuse I just recently fixed my Maxima by accessing the code and changing out a bad coil and I also replaced my plugs. By the way; The dealer wanted 200.00 to chage plugs. It cost me 50.00 for the plugs and 1/2 hour of time to do the same job and in that 1/2 hour I also replaced a coil. THEY ARE THIEVES. It really is obscene what they charge. It cost me 100.00 to have a key made the other day.....
 

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Sorry it ended up being later on this month, and not day. I could not come up with the way to do it through the light. I dont want to give you the wrong info, but it is prbly like my car with a little diag screw on the ecu. Here are the problems with this info:
1. Im not sure if it has the screw.
2. If it does, I could not find a code list.

Go ahead and hit Sentra.net if you are curious about it. The site has a section on how to do it for a Sentra. If it is the same procedure thats good, but the code list would have differences.
 

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traderfjp,

I've got a 1990 Pathfinder. I am the original owner and have had a problem with my Check Engine Light since I bought it.

The light comes on periodically and always indicates an "injector leak" which I know I don't have. I took it to the dealer when I first purchased it and they would tell me the code "45" "injector leak" and then the light would stay out because the system is reset by their computer when it checks the code.

They would hook up their computer to the wiring harness under the dash around your left knee area.

Since the problem went away everytime they reset it, they told me it was just being overly sensitive and those systems are notorious for giving false alarms. I have checked the injectors also several times and found nothing wrong, so I've basically put up with this little periodic annoyance for 12 years now.

I have learned through my experience with my Haynes Repair Manual that there is another way you can check the code without taking it to a mechanic. Under the passenger front seat is the Engine Control Unit (ECU) of your Electronic Concentrated Control System (ECCS).

There are 5 modes to the ECU, mode 3 being the self-diagnosis mode.

1. Put the key in the ignition and turn the ignition to On without starting it.

2. Take a flat head screwdriver and locate the screw in the rear of the unit under the right front seat. (It may help to move the passenger seat forward and flip the seat back forward. I find the easiest position for viewing from the driver's seat looking at it upside down leaning over the console, but it may be confusing to try this procedure upside down for the first time.)

3. Turn the screw clockwise until it stops. Keep the screwdriver in the slot so you can turn it back the other way when you need to below.

4. Count the number of flashes to see what mode you are in.

5. When it flashes 3 times to indicate mode 3, turn the screw back counterclockwise all the way. You are now in the self-diagnosis mode.

6. There is a red light and a green light. You will get so many red light flashes and so many green light flashes to indicate the code. (i.e., 4 red flashes, 5 green flashes is code 45.) The codes are listed in the Emissions Control Systems Chapter of Haynes manual. It is on page 6-23 of the 1980 through 1991 version.

7. After you get the code from mode 3 turn the screw back clockwise all the way and go through at least code 4 and it will reset the system. ( Operating the starter 50 times will also reset the system, so if nothing is wrong the light will eventually go out.)

The system is supposed to go back to mode 1 after the power to the ECU has dropped off and then turned back on with the ignition key.

You can PM me or post here and I will try to get back to you with what your code indicates. Most likely if the vehicle isn't running differently there is nothing wrong and resetting the light is all you need to do.

Hope this helps and I didn't just confuse you.
 
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Discussion Starter #8
traderfjp said:
Hi,

I have a 2001 Pathfinder SE. My service engine light went on. My truck is off warranty and I would like to access the computer codes myself. An anyone tell me where the computer is on the Pathfinder? Also, is there a site that tells what each code means. I found one for the maxima if anyone is interested?

I checked my gas cap and it was on tight and the truck runs great. I was about 1/8 of a mile from a bolt of lightening that hit. It made a few car alarms go off and my truck was running. I have a feeling this might have set it off.
I also have a 2001 Pathfinder SE and my Service Engine light came on about 3 weeks ago. My situation sounds exactly like yours - Service Engine Soon light just came on while driving down the road and no change in performance whatsoever. I spent about a week searching on the web to see if there was a way to diagnose what the problem was and how to fix it myself (didn't want to pay a mechanic a ton of money for something that would probably take 5-10 minutes to fix myself). While searching, I ran accross this thread. I assumed that once the Service Engine light came on, the only way to shut is off was to reset the computer. I also almost bought a code scanner for about $75 - $100 to help diagnose the problem. Turns out that the problem was a very dirty air filter. Once I changed the air filter, I fired my truck up and the Service Engine light was no longer on and hasn't been on since WOO HOO!!! And I didn't have to buy a code scanner or pay a mechanic to fix my Pathfinder (which would probably have told me an emissions part needed to be replaced and charged me an arm and a leg).

*If you're light is still on, you might want to try the same thing.
 
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Discussion Starter #9
odd check engin elight occurance

I live near atlanta and i was going to charleston s.c.
I was about 3 hours into the trip and my check engine light was on. Now this was my first trip by myself (im 17) and i havent gone anywhere more than 45 minutes. but anywho, i called my dad and he said if theres no smoke or if its not driving bad then its probably a maintainance light since i just hit 75,000 miles. I took it to Auto Zone for their free engine check light diagnostic and they sed it was an o2 sensor. I was saving up money so i could take it in and in the mean time the light went off and hasnt been on since.
 
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