1994 Nissan Sentra LE manual code retrieval

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#1
I read the information in the Trouble Codes section for Nissan, but the information does not match my situation. My ECU does not have the diagnostic mode selector; it only has the ALDL access port. Is there a way to do a manual jumper to access the stored codes?

Thank you,
Rick
 

Paul

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#2
Which engine does it have and post the date the car was made.
 
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#3
Hi Paul, I meant to include that info first time around. My apologies for wasting your time.

Aug 1994 and 1. 6L 5 speed transmission

Nissan Sentra LE (Limited Edition)

I found another web site that had a pdf document that said Nissan stopped making 1. 6L Sentras in 1990. It is: "#3173
IMPORT COMPUTER CODE READER. " I do not know who published that document. This document also said the special tool for retrieving codes isn't needed for 1991 and newer Nissan Sentras.

Here is actually an excerpt from the document:

"OVERVIEW OF NISSAN/INFINITI DIAGNOSTIC SYSTEMS
Retrieving codes from Nissan/Infiniti vehicles requires the use of the flat end of the code retrieval tool shown in Figure N1.
Nissan/Infiniti vehicles use a variety of computer systems which are equipped with either a single-LED (Light Emitting Diode) or a dual-LED display.
To retrieve codes, you need to first locate the LED display on the vehicles computer. The LED(s) are mounted inside the computer, but may be seen by looking through an opening in the top of or on the side of the computer housing. In some cases you may have to remove the computer from its mount.

NOTE: Refer to the vehicles service manual when removing the computer from its mount, as it is easily damaged.
All Nissan/Infiniti vehicles covered in this manual are equipped with a screw-type diagnostic mode selector on the vehicles computer. The diagnostic mode selector is accessed through a cutout in the computer housing. Two marks show the operating
limits of the diagnostic mode selector. The Code Reader is used to adjust the position of the diagnostic mode selector (N2).
NOTE: Some Nissan/Infiniti models do not require a tool to retrieve codes. The Tool Req? column in the Code Retrieval
Procedures Tables on pages 24 through 29 will let you know if a tool is required. If no tool is required, just follow the
procedures as indicated to retrieve codes. " (The chart shows a tool is not required. )

Here lies the problem. There is no screw-type diagnostic selector. There is only an ALDL access port. I do not have the right connector to connect to the access port, and my scanner OEM says there isn't one available because of the age of the car. I tried contacting a local Nissan dealership, and I was told they couldn't give out that information "due to liability issues," whatever that means. Hence my question, how do I manually access the codes? Is there a way to do that? So far I haven't been successful in finding the answer, and I've looking for several weeks, now. I came across your website for the first time last night, and I sure hope you know the answer.

Thank you,
Rick
 
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#4
should be an access hole in the side of the ecm.using a screwdriver,turn it all the way clockwise.if the ecm has a single led lite,count the flashes.there will be a pause between the first digit and the second digit of the code.if the ecm has a dual led display,turn the screw in the access hole all the way clockwise.at this time the leds will flash once for mode 1,twice for mode2 and three times for mode 3.mode 3 is diagnostic mode.when the leds flash three times,turn the screw all the way counterclockwise.count the number of flashes on the red led,this is the first number of the code.then count the flashes on the green led,this is the second number of the code.after retrieving codes return the screw to its origional position.to clear codes without a code reader disconnect the battery for 24 hours.
 

Paul

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#5
OK,Forget other websites.The reason I asked you the manufacture date is because it may very well be OBD II,Once again,when was the vehicle made?
 
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#6
Hi Paul, I said Aug 1994, second line from the top. ;-) It is EPA tagged as 1994, and it is registered as 1994, most likely because it was made with the ALDL connector, rather than the new industry-wide agreed standard of OBDII. I have taken a picture of the connector which I can email to you, if it would help you. I use gmail, which automatically scans for viruses. The connector is rectangular with straight sides, not the tapered sides of OBDII. The ALDL connection is at the bottom of the fuse panel, which is on the left side, at the bottom of the dash.

This ECU does not have an access hole. The ECU is in the middle of the dash, behind and under the radio. I had to tear into the dash to get to the ECU. I have had the ECU apart looking for anything that could be used for manually retrieving the codes. The codes were accessed once manually, by another shop, and from what I understand, the mechanic used a wire or some other kind of connector that was not designed for the Nissan, but it worked to get the codes. I do not know what was used.

I was told by a Nissan service man this particular ECU was only used in the Sentras for two years: 1994 and 1995. However, I do not know if he is correct.

I truly hope you can help me.

Thank you,
Rick
 

Paul

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#7
If your scan tool has a connecter for generic OBD II,try it.My scan tool has that connecter and I have used it succesfully on other models.Thats about all I can tell you.1994 and 95 were transitional years for a lot of manufacturers when it came to diagnostic terminals.Good luck with it.
 
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#8
Hi Paul, thank you very much for trying. This car is definitely an oddball! Maybe I should try twisting the arm of that guy at the local nissan dealership. ;-) If or when I do get this information, I'll try to remember to come back here and post it, in case someone else runs into the same problem I've had.

Thank you,
Rick