Here one of my readers has divulged the secret of reading the stored computer codes in his 1996 Nissan. He also points out the value of having the manufacturer's shop manual for serious diagnostics!!

Yes Virginia, when the (MIL) Malfunction Indicator Lamp comes on in your Nissan 200SX you can read the failure code(s) yourself without a $2,000.00 piece of test equipment.

A couple of weeks ago my MIL light came on in my 1996 Nissan 200SX. After calling around, chasing Snap-On trucks down the highway, etc. I kept getting the same story. Oh! you need a diagnostic tester and it will cost you over $2,000.00 to get one. I did find a dealer that sells an inexpensive one that reads the codes only, no fancy diagnosis, for about $150.00. I tried a dealer but of course they needed me to make an appointment and the charge would be $66.00 for them to use thier fancy tester to tell me what my car should be able to tell me without them.

However, when I purchased the car I also sent away for the $107.00 service manual. I bought all the service manuals for my brand new 84 Cougar and they have paid for themselves many hundreds of times, I still have and drive that car. Only need a crummy $6.00 analog meter to read the codes out of that car.

Anyway, here's how to read the codes from the Nissan: When sitting in the driver seat of the Nissan 200SX, by your right foot, under the console, behind your radio, and bolted to the hump between the driver and passenger sides you will find the cars diagnostic computer system under a plastic cover. There are 2 nuts attached to bolts in the front and 2 phillips screws in the back (one per side). Remove the 2 nuts and 2 phillips screws. You will also need to pull out the plastic inserts that the screws go into.

On the back of the assembly is a flat piece of metal that slips under a clip. After the nuts, screws and inserts are removed lift the front of the assembly and pull it forward (cover and all). Now work the assembly and the cover together over to the passenger side. There is not enough room to take off the cover so you need to move the cover and the computer at the same time. Of course, be careful of the wiring harness. You should be fine if you are not rough with it.

Once you have the computer over on the floor of the passenger side remove the cover and turn the computer around as best you can so that you can see the back of it. On the back of the unit under a clear piece of plastic tape you will see a flat-head screw. I peeled it back so that I could put it over the screw again. NOTE: The normal position of this screw and turned completely counter-clockwise. Insert your key into the ignition and turn it until the dash lights come on. DO NOT START THE CAR. You should now see all the dash lights steady on including the yellow MIL light. Now turn the screw on the computer completely clockwise; the yellow MIL light will go out; wait about 3-5 seconds and turn the screw completely counter-clockwise to where it was originally. You have just switched the computer from diagnostic mode 1 to diagnostic mode 2 and within a few seconds the yellow MIL light will start to flash the failure code(s). The codes are 4 digits (XXXX) and are read as follows: The first two digits are given first (the tens digits) by .6 second flashes and then the second two digits are given (the ones digits) by .3 second flashes. My particular failure was 3 long flashes (03XX) and 3 short flashes (XX03). So my code was 0303.

If you do not want to erase the code(s) you can simply turn your ignition completely off and wait for more than 5 seconds. The computer will automatically switch back to diagnostic mode 1 and the failure codes will still be there (the MIL light will still be on). If you do want to erase the codes and turn the MIL light off again just turn the screw completely clockwise and wait 3-5 seconds and then turn it completely counter-clockwise again.

Manually switching from diagnostic mode 2 to diagnostic mode 1 causes the failures to be erased from the memory of the computer. You are also supposed to be able to erase the codes by disconnecting the battery and waiting 24 hours for the memory to erase itself but to put it bluntly THAT SUCKS POND SCUM. You should be able to find a listing for the engine codes on the internet, maybe on this wonderful site right here. My failure code came out to be that the number 3 cylinder had misfired.

Funny, the car runs great and I have never noticed anything rough about the engine. So I reseated the spark plug wires at the distributor and spark plugs, turned off the MIL light and put the computer module back where it was. So, I did not have to take time off of work to go to a dealer and pay a minimum of $66.00 dollars to have somebody else reseat my spark plug wires.

Book 1, Dealer 0. $107.00 - $66.00 = $41.00. Looks like the book is well on its way to paying for itself.

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