1996 Nissan Maxima P0500 CEL SOLUTION!

speedometer
maxima

#1

I have a 1996 Nissan Maxima that has been driving me crazy for about 3 years with an intermittent problem. I’d be driving on the freeway, and the cruise control would quit. Sometimes, the O/D light would flash (I didn’t count the number of flashes), and the CEL would come on.



Hook up the OBDII scanner, and got a P0500, which means “Speed Sensor.”



However, it could not be the speed sensor, because the speedometer would read correctly. I point this out because some of these cars would read 0 mph, or the speedometer would fluctuate wildly. When that happens, it is the speed sensor or the wiring between the sensor and the speedometer.



With my symptoms, the problem had to be between the speedometer and the ECU. A signal comes off the back of the speedometer and feeds the ECU; this way, the ECU can tell how fast the car’s going.



It turns out this last point is more important than I thought. If this signal is flaky, the ECU will be constantly fiddling with the timing and mixture, even though the car is driving at a relatively steady speed. In retrospect, I can see that the car was surging when I set the speed.



I changed the speedometer. Problem solved.



It took about 2 hours. All you have to do is take off the kick panel, the knee bar, the shell around the steering column, and the fascia around the instruments. The cluster then comes out with 3 screws. You can have one out in 20 minutes.



Only 4 screws hold the speedo in place.



A dealer in Texas sold me a new speedo, set to the same number of miles as the speedo in the car (I kept all the paperwork).



The independent garage near my work wanted 6 hours labor for this job! I did the job in 2 hours.



I just wanted to publish this success story because so many Nissans from this approximate era have this same problem. There is hope for you. I saved myself probably $400 doing the job myself, and it’s really not that hard.



If you need more details on this job, I’ll be happy to provide them.



Good luck!


#2

Thanks for sharing that fix, Mike. On the Nissan, the VSS (Vehicle Speed Sensor) signal go to the Electronic Speedometer FIRST; then the speed signal goes to the engine computer. On other car makes, the VSS signal goes to the computer, first (which I think is a better idea). The bad effect by the Electronic Speedometer, messed up the engine computer signal.


#3

Hi, Mike. Thanks for this info. I have a '97 Maxima. I have a similar challenge. My “service engine” light went on and the mechanic gave me the P0500 reading. After careful monitoring I realized my speedometer was not always reading the speed, but usually just for a minute or two and only in cold weather. The mechanic checked the wiring and the speed sensor and said that wasn’t the problem.

I’m not sure if my solution will be the same as yours but I don’t think it would be wise for me to attempt a self-repair. Could you suggest how best to guide the mechanic on where and what he should be looking for?

Any insight you have would be very appreciated. Thanks.


#4

Show your mechanic this: http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c15280076347


#5

I’m in the same boat with the check engine light, shaky speedometer etc. but I have a 97 Maxima. What is most common in this case? The speedometer or the sensor? I need to get it fixed ASAP so I can renew my tag. Thanks so much!