03 04 - knock sensor

01 04 - vehicle speed sensor

05 04 - Automatic Transmission Control Unit Signal to ECU


I don't know what to think about these. Any ideas? Car runs perfect, this seems peculiar to me. 93k miles on a '97, by the way.

 

Well, to help you out any, I got the 0504 code once. Ironically, it didn't set the CEL off. It happened to come up when my Overdrive lamp started blinking. But, it went away, after I reset the computer. I tripped the transmission computer because the car missed a gear (probably downshifting) when I slammed on the brakes real hard in avoiding an accident. As far as the vehicle speed sensor, this maybe just related to a speedometer problem. Happened to my freind's Altima once. Try extracting any codes from the transmission computer. This will tell you exactly what part of the transmission needs to attended to.

 

Thanks for the response. Where's the transmission computer?

 

The AT and speed sensor codes can come from unhooking the speed sensor to get around the governor. Have you done this?

 

How do you pull codes from the transmission computer. I have never done it. I also got the transmision computer error code 0504. But reset the ECU and it hasn't come back yet. But i would like to see what codes are on my trani computer. Thanks.

 

i got the knock sensor code also, now that you guys mentioned it could be realted to the spedometer makes me think thats whats wrong with mine. My spedometer every now and then drops down to zero and the odometer stops counting momentarily till the spedo jumps back to read the speed. But the tachometer doesnt seem to be affected by that, it keeps on reading the RPM's.

Have any of you had this problem? do u guys have any ideas of what it could be or how i can find out?

 

Actually, the transmission computer is related to the ECM. It's located opposite of the ECM on the front passenger side, behind that black trim cover plate. There's a Data Link connector for it, but only professional transmission shops have the scan tool for the consult. I don't believe its available for the home mechanic (maybe, for the simple reason that the transmission for us Maxima owner's is very complex--as said in the Hayne's manual). But, we can sure extract any faulty codes. It seems rather complex, as explained in the Hayne's manual (Chapter 7 pages 7B-2 and 7B-3), but at least we can find out what is actually wrong with the transmission if something goes wrong. Actually, each time you start up your car, the "overdrive" lamp is an indicator of how your transmission is functioning. If it happens to flash after start-up, or flash during normal driving, more than likely there something faulty with the transmission. Extracting any codes will give us an indication of what tripped the computer. Believe me, I got the 0504 code once (in the ECM), and after extracting the code in the transmission computer, I got a "no-fault(s) found". My "overdrive lamp" flashed after start-up, but then it stopped. It seemed to reset itself when my car wouldn't "drive" right as explained in my previous post. Also, the 0504 code does not trip the CEL!

 

I haven't made any changes. I turned the light off last week and now it's back on so I'll have to see if it's just one code or all 3 this time. May have to go to the shop....