I have a 95 Z28.
My ses light is coming on a minute or so after start up. I'm running scan9495 and I'm not getting any code. The fan continuesly runs when the light is on. Does anyone know what could be causing this to happen any help is greatly appreciated and thank you in advance. It is not effecting the way my car is running but it is driving me crazy seeing the light come on and not being able to fix the problem

 

Clear the PCM by pulling the “PCM BAT” fuse for 30 seconds. Run a data log from a cold start, idling, until the SES light comes on, then continue for another minute or two. Attach the .csv file to a post. I'll download it and see if I can spot the problem.

 

I am not very savvy with computers and I hate to even ask you this but how do I go about doing that. I pretty much bairley know how to hook it up and scan it.

 

Does this help any

 

Is it possible you can’t pull the code(s) that are turning on the SES light because Scan9495 isn’t hooked up right, or you aren't using the correct screen? Did you get the correct OBD-1 16-pin cable?

I don’t use Scan9495 on my 94 because I don’t use the stock PCM to run my engine. So I can’t provide the details of how to use Scan9495. But I can interpret the data log, and have done so for 100’s of members.

 

You posted the screen shot while I was typing the above response. If the system is able to produce that screen shot, appears it’s connected and working. You just need to find the way to start the logging function. Start the logging just before you start the engine. Continue logging until you shut the engine down. There will be an option to export the data log as a .csv file. Typically you will end up with what looks like an Excel spreadsheet, with more than 50 columns (one for each of the items described in the yellow boxes), and maybe 2,000 lines of data showing the number values, equivalent to 2,000 screen shots.

Most of the data in your screen shot looks correct, but a single screen shot (frame) of data doesn’t show how the data changes with time. It is odd that the screen shot shows both fan relays have been turned on. Normally, the only occurs when the coolant temperature reaches the values programmed in the PCM - 226°F for Fan relay 1 (both fans on low speed), and 235°F for both fans on high speed. After running for 245 seconds, your coolant temperature is still at 106°F. We need to see when in the log the fans are switched on. That could be a response to some other fault in the system that causes the PCM to turn on the fans to protect the engine.

The O2 sensor readings also look odd. One reads very rich and the other reads very lean. In open loop (as confirmed by the screen shot) they should be very similar.

The author of Scan9495 is a member here. If you can’t figure out how to start the logging process, I’ll see if he can help out.

 

My pcm is stock. I don't have a pcm batt fuse that I'm aware of. There is one under the hood that says pcm and one on the driver's end of the dash that reads pcm ign. I wasn't sure witch one of those was the batt so I pulled both for 30 seconds. I also thought it would be helpful if I told you that I have done an egr as well as a throttle body coolant delete.

 

I'm going to run out there here in about 5 minutes and see if I can figure out how to get that program to log. I also have an innova scanner but I never could figure out how to get it to read. It is supposed to be obd1 and 2. It has a bunch of different ends for it

 

The PCM BATTERY fuse is #8 in the under hood box:

http://shbox.com/1/1995_pcm3.jpg

Several of the Innova scanners have an incorrect data base for the LT1 PCM, and produce a bogus list of 7 to 10 invalid codes. Avoid Innoa and Equus scanners.

Throttle body coolant has nothing to do with the PCM or codes. If EGR is deleted, it can set one or two codes, depending how you deleted the system, either DTC 27 for the EGR vacuum solenoid, or DTC 32 when EGR flow is not detected by a change in MAP sensor readings. EGR isn't used at startup, not used at idle, so it isn't setting a code on cold start. Deleting EGR does more harm than good. EGR does not impact performance in any way - it is not used at WOT, not used above 3,500 RPM. But it does help prevent detonation (knock) when lugging the engine at in wrong gear at low RPM.

 

I was able to figure out how to hook up my snap on scanner to it used the obd1 end from my innova scan tool that actually fits the snap on. Why I never thought of that before is beyond me. Anyway it is giving me a knock sensor fault and a throttle position sensor. I'm going to go ahead and put the egr back on it as well. I'll start there and see where it takes me. Thank you for your time and willingness to help. If I have any further concerns I will post it on this thread.