MIL on but no OBD code?

daemath · Aug 24th, 2004, 09:45 AM

The MIL came on in my 2002 Sentra GXE (45K miles). I checked it with an Equus code reader---code came up as 0 (no codes stored, nothing pending). I retightened the gas cap and reset the light; after two trips it came on again.

Checked with the reader again: no codes, but the oxygen sensor monitor, catalyst monitor, and evaporative system monitor lights on the reader were flashing, which (according to the reader manual) means "the monitor has not yet run its diagnostic testing". I drove the car around for 15 minutes with the reader plugged in to see if additional time/higher temperatures would do something, but still didn't get any code. I disconnected the battery for an hour, which still didn't reset the light(?!), then reset it with the code reader. After two trips it came on again; same problem with reader having no code and indicator lights flashing.

I read on the Web that sometimes a "0" code will pop up if the reader can't access certain parts of the computer, and you have to use a Nissan-specific reader. (I've used my Equus on my Pathfinder and gotten Nissan-specific data before, though.)

I'm thinking about taking the car to AutoZone to see if they can pull a code---or will they use the same type of reader I have? Do I have to go to a dealer to get someone who can get the code? Will the "stepping on the accelerator to read codes" trick (as described in http://www.nissanforums.com/showthread.php?)
work on my model? (I'm getting conflicting info from the postings.)

Any thoughts about what might be causing this? My repair confidence level pretty much tops out at replacing hoses, but I'd like to have some idea what's going on before I take it in for repairs.

Thanks in advance for your help.

**chimmike** · Aug 24th, 2004, 11:19 AM

as far as i know, the equus stuff is crap. definitely take it to autozone and get the code checked.

also, try unplugging the negative terminal of the battery for 10 mins, which resets the ECU. if there really is a problem, the CEL will come back on.

daemath · Sep 16th, 2004, 08:59 AM

I took the car to AutoZone; their reader immediately picked up a P0051, low voltage in an O2 sensor. My reader is still under warranty, so I'm getting a new one.

FREDANDTA · Sep 16th, 2004, 09:27 PM

Quote:

Originally Posted by daemath

The MIL came on in my 2002 Sentra GXE (45K miles). I checked it with an Equus code reader---code came up as 0 (no codes stored, nothing pending). I retightened the gas cap and reset the light; after two trips it came on again.

Checked with the reader again: no codes, but the oxygen sensor monitor, catalyst monitor, and evaporative system monitor lights on the reader were flashing, which (according to the reader manual) means "the monitor has not yet run its diagnostic testing". I drove the car around for 15 minutes with the reader plugged in to see if additional time/higher temperatures would do something, but still didn't get any code. I disconnected the battery for an hour, which still didn't reset the light(?!), then reset it with the code reader. After two trips it came on again; same problem with reader having no code and indicator lights flashing.

I read on the Web that sometimes a "0" code will pop up if the reader can't access certain parts of the computer, and you have to use a Nissan-specific reader. (I've used my Equus on my Pathfinder and gotten Nissan-specific data before, though.)

I'm thinking about taking the car to AutoZone to see if they can pull a code---or will they use the same type of reader I have? Do I have to go to a dealer to get someone who can get the code? Will the "stepping on the accelerator to read codes" trick (as described in http://www.nissanforums.com/showthread.php?)
work on my model? (I'm getting conflicting info from the postings.)

Any thoughts about what might be causing this? My repair confidence level pretty much tops out at replacing hoses, but I'd like to have some idea what's going on before I take it in for repairs.

Thanks in advance for your help.

That code reader will only pick up obd II generic codes. u might need a snap on scanner, geneisis, or mastertech to get to the bottom of this because these will read the generic and nissan sides of the ecu to extract data.