Well for OBDI cars I'm pretty sure they just check to see if the CEL is on, then probe the tailpipe emissions. Plus all the other little things, like the gas cap. Someone correct me if I'm wrong.

I couldn't imagine every smog shop having every interface for OBDI.

 

that's what i thought, thank god.

 

If the mechanic has the $$$$$$$$ Nisan CONZULT interface, he'll scan it. if not, he'll say "you car needs to be fixed" and thats it. OBD1 are nto required to meet such high standars in emissions.

Its like those muscle cars and old cars. They don't have computers, they are not requiered to pass emission test as far as I know. Of course, its not like you can drive with a huge black wall of smoke behind your Charger and not get pulled over.

 

Sorry to bring up a dead subject, but this thread involves an issue I'm having. I followed the directions above to read a code on the ECU, and I got 3 long flashes, followed by 3 short flashes. I only have a red light, no green. According to the list above, that would indicate code 33, a bad "heated oxygen sensor"... do our cars even have these? I also checked the list in my Chilton's manual, and code 33 for that one is "Exhaust Gas Sensor Circuit." Which one of these issues should I be pursuing?

 

sounds like you got lost in the mode cycle because what you have is code 30 which i can't find anything about on this engine. but yes you may have a heated o2 sensor. i say may because they were just beginning to be used around the time the car was made.

anyways you should check for codes again because it seams to me that you made a mistake somewhere. which is not hard to do when reading codes on this particular obd 1 ecu.

 

Why would that be a 30, and not 33? It kept repeating, and the pattern was the same, but I inadvertently reset it. However, I changed the O2 sensor today, and I did the Mode 2 "on" test for the Exhaust Gas Sensor monitor ( https://www.s-chassis.com/forums/how-tos-installations-48/diagnost-ecu-codes-41051/ ) and it did fine, so I'm going to take it to emissions tomorrow, and see how it goes!

 

that's just it the code repeat unless you're in mode V in which the code are only shown once. mode II uses the red and green led to display if the air/fuel mixture is lean or rich. however both leds should light up simultaneously or both stay off. you need to run mode III to get codes.

also there is some misinformation in that link so you should dl a fsm.

 

Thats the thing, I don't even have a green light in my ECU, I think that is only the newer ones that do? Anyway, I think I have the FSM downloaded somewhere, I'll try to find that and check it out!

 

there should be a sticker on the side of the ecu with a number, what is it?