Intermittent Speedo, Dash warning lights on, Puzzling me???

[Corvettelvr73]

Last week while driving the BRAKE, SLIP, VDC OFF, KEY, ABS lights came on and my speedo went to zero. While continuing to drive the speedo would intermittently bounce to the actual speed for a sec or 2 then back to zero then pulse up, back down a few times quickly. Every few minutes with no apparent pattern or speed range the speedo will do this but mostly it stays at zero. After a day of driving with the lights on the Service Engine Soon mil came on and i went to the Auto parts store and checked the codes and had the battery tested. the battery was 98% and the code was P0500, which is a Speed Sensor error code. I am not low on brake fluid either. OK after many hours of researching this forum i have not found anyone to have the exact same symptoms as I. The service manual is not much help either because everything says to plug in the CONNECT II diagnostic computer which is too expensive for me . I took it to an independent Infiniti/Nissan/Datsun shop and they said there are a few codes coming up and it seems that the ABS Control Module is not communicating with their diagnostic scanner. I am taking it back on Monday because they said they need more time to work through the diagnosis as it was 4:30 in the afternoon and they have not experienced an M35 ABS module not communicating with the scanner. I forgot to get the list of codes from the mechanic. The car seems to drive normally the transmission is shifting as it did before as far as I can tell. Has anyone experienced or have any ideas what is going on. It is a 2006 M35 base with no extra options 103,000 miles. I just like to educate myself and avoid service shops at all costs. I have not had any issues with this vehicle since i purchased used with 13 K miles and now I have a feeling it is "the BIG one" (if you remember Fred Sanford). The KEY dash light really confuses me because It doesn't come on all that much according to snooping around on the net. Thanks for any input anyone might have.

[DeanM45]

Sounds like the transmission revolution sensor has gone bad. It is not too dificult to replace but if you are not mechanically inclined I would not attempt. You have to remove the transmission pan and tailshaft of the trans which may or may not require driveshaft and exhaust piece removal. The sensor is the accessible (single bolt) once the tailshaft is removed. Have the shop check for the additional codes but more than likely it is the revolution sensor (VSS Sensor).

[Corvettelvr73]

That's what I was thinking from reading the service manual however I didn't not know where it was located and could not find a picture or part number on the internet. Thank you for your thoughts. I will look more into the revolution sensor.

[Corvettelvr73]

Diagnosis ended up being a bad ABS Control Module. Local Nissan/Infiniti/Datsun shop diagnosed and repaired. $716 total, used pump module $379, Labor $287, rest taxes and brake fluid and shop supplies. Not bad in all except I worry about the used part but $1500 for the new part is ridiculous. Just wanted to let everyone know what solved my problem. Thanks

[DeanM45]

Interesting. Never would have thought that. Thanks for letting us know!