Check Engine Light

[vicki]

Hi guys,

Edit: it's a 1995 240sx SE at

My check engine light keeps coming on although I've checked all the fluids and the car seems to drive fine sans the slightly rough acceleration. I've concluded that it probably has something to do with the ECU codes. I can fix the EGR and I'll probably have to replace the knock sensor but I'm having trouble locating the A/T diag comm line. I've done a search and came up with nothing so my questions are:

Where is the location? What is it exactly and what does it actually do?

Any help is appreciated. Thanks. I've just ordered the FSM on ebay but hopefully you guys can help me figure it out before that gets here.

[NISTECH]

The AT comm line is the wire between the ECM and the TCM. What that code means is the ECM did not see communication From the TCM when it expected it. This could be due to a loss of speed signal its pretty common.

[vicki]

How can it be fixed?

Is there anything to be replaced?

[NISTECH]

It could be the speedo. what were the codes stored in your ecm. I have a factory service manual here at home on my other computer I can look them up to be sure what your chasing and even get you diagnostic procedures.

[NISTECH]

BTW welcome to NICO

[vicki]

BTW welcome to NICO

Thanks sweetie.

I'll get the codes tomorrow and let you know.

I appreciate it.

[vicki]

The codes are 32 - EGR system, 34 - Knock Sensor, and 84 A/T Diag Comm Line.

I have just purchased a PDF Factory Service Manual from eBay.

[NISTECH]

so you have the procedure? As I remember it just involves ohm checking the wire between the 2 control units for the A/T code. on your egr check the hose just below the BPT,on the knock sensor it is likely cracked and or has an open circuit between the sensor and the subharness.

[nab911]

Hell we could have gotten you that, but anyways. The egr is the big UFO/disk looking thing right behind the valve cover. Its about the size of a silver dollar. That right there is the EGR valve. It has a tube that runs from it, into your exhaust. A lot of time this tube can get clogged with crap, so if you can get it off, just clean it first. Also, if you have a big exhaust leak/little backpressure, it can make the egr no operate properly because it has to open and pull excess fuel from the exhaust before hit its that rear o2 sensor.