96, I-30 Knock Sensor & Speed Sensor

First, fix the speed sensor and check with the Factory Service Manual if the speed sensor code can also trip the knock sensor code. Knock sensor code can be tripped by many other codes. A faulty knock sensor will only reduce fuel economy until it's fixed. I don't know what's involved in replacing the speed sensor.

Then, if you clear the codes and the knock sensor code appears by itself, you can replace it. It is a DIY job, but you'll need a 12mm flex-head 1/4" drive socket, and a 14" 1/4" drive extension. The part is around $100 from eBay or a discount Nissan parts dealer. Also really long needle-nose pliers. With this combo, you can sneak that onto the bolt holding down the KS without removing the engine intake manifolds. On reinstall it's a little tricky - I used a small piece of tape on the head of the bolt and twisted around onto the socket so I could position it in the hole without it falling out.

All in all, a 10min job once you figure out how to do it. I recommend going to

or and searching for past discussions on the knock sensor and speed sensor. There is a great deal of info between those sources.

Dave

first things first

the knock sensor will NOT turn on the check engine light, no matter what !

The knock sensor code will be stored in the ECM's memory , that means that if you pull the codes without the CEL being on the knock sensor code may be stored.Nothing will "trip" a knock sensor code, it shows up when the ECM determines it has fallen out of it's specified acceptable preprogrammed range.

As for the P0500 code. there are 2 speed sensors that the ECM uses

one of them is in the transmission and the other is inside the speedometer head, I bet the guys at Auto Zone didn't tell ya that.

The SS in the transmission will almost NEVER go bad ( at least in my 17 years as a tech I have never seen one go) but the one in the speed-o head will.To fix the P0500 code the speedometer head needs replacing ( see thing more times than I can count)

Greetings!

Recently I noticed my dashboard "Automatic transmission light" on my 1995 Nissan Maxima suddenly appears to be on and it won't go off. My car has the original transmission with 85k miles.

I took it to Jiffy Lube for the routine oil change and fluid check and the transmission fluid levels are normal with no apparent leaks.

They said it could be a bad "Transmission Sensor" but I'm afraid to take it to a transmission shop because I don't want them to overcharge me for unnecessary repairs for something that I don't need. Anybody heard of this before? Any personal experience advice about how you resolved this problem in the most cost efficient way would be greatly appreciated. Thanks in advance for sharing your expertise.

Bruce

Phoenix, AZ.

Marcus,

I also had a P0500 (aka DTC0104). In my case, cleaning the connectors on the flex PCB on the back of the speedo cluster fixed it. Please see this thread for more info.