Scan9495: Free OBD1 scan app for 93/94/95 LT1
Registered User
Joined: Mar 2016
Posts: 5
Re: Scan9495: Free OBD1 scan app for 93/94/95 LT1
GaryDoug let me know where to send money (SERIOUSLY) paypal?
this is awesome- followed the instructions- paid for a good cable came with a CD- worked as advertised..
will be doing a real scan (driving) in the morning...
I cannot thank you enough
this is awesome- followed the instructions- paid for a good cable came with a CD- worked as advertised..
will be doing a real scan (driving) in the morning...
I cannot thank you enough
Thread Starter
Prominent Member
Joined: Jul 2010
Posts: 1,519
From: Born on the Florida West Coast, now where can I retire?
Re: Scan9495: Free OBD1 scan app for 93/94/95 LT1
No need for any money, I can do without it. Just pass the word on and let others know.
Perhaps you could do me a small favor instead? Takes just a few minutes.
Perhaps you could do me a small favor instead? Takes just a few minutes.
Thread Starter
Prominent Member
Joined: Jul 2010
Posts: 1,519
From: Born on the Florida West Coast, now where can I retire?
Re: Scan9495: Free OBD1 scan app for 93/94/95 LT1
I hope you can assist with this little task. if you have a running engine.
Remove both injector fuses from the underhood fuse/relay box. This is to temporarily keep the engine from starting. Crank the engine for a few seconds as usual while watching the tachometer. Note the position of the tach needle while cranking. Try to estimate the rpm indicated. If possible, take photos of the gauge in the "off" position and the "cranking" position and post them here. Or email them to scan9495@gmail.com. Put back the injector fuses. The goal is to see what the actual reading is for the tach while cranking the engine.
Thanks if you can do that. I have been relying on hearsay to advise folks about reading the tach while cranking, but I don't have a car handy to see for myself. This can help some people with their issues.
Remove both injector fuses from the underhood fuse/relay box. This is to temporarily keep the engine from starting. Crank the engine for a few seconds as usual while watching the tachometer. Note the position of the tach needle while cranking. Try to estimate the rpm indicated. If possible, take photos of the gauge in the "off" position and the "cranking" position and post them here. Or email them to scan9495@gmail.com. Put back the injector fuses. The goal is to see what the actual reading is for the tach while cranking the engine.
Thanks if you can do that. I have been relying on hearsay to advise folks about reading the tach while cranking, but I don't have a car handy to see for myself. This can help some people with their issues.
Thread Starter
Prominent Member
Joined: Jul 2010
Posts: 1,519
From: Born on the Florida West Coast, now where can I retire?
Re: Scan9495: Free OBD1 scan app for 93/94/95 LT1
Here is the result. Tach needle starts at zero and moves up to maybe 200 RPM while cranking. Thanks to "laserpaddy" for the image from his video. Now we can say for sure what the tach looks like with a good Opti.
Last edited by GaryDoug; Mar 24, 2016 at 09:35 PM. Reason: add link
Thread Starter
Prominent Member
Joined: Jul 2010
Posts: 1,519
From: Born on the Florida West Coast, now where can I retire?
Re: Scan9495: Free OBD1 scan app for 93/94/95 LT1
A user of the app has found an error. The app refers to DTC83 as applying to the manual transmission only, and it would be correct if the user has a manual transmission. However, the app does not also show the description for DTC83 that applies to the automatic transmission. They are different descriptions, even though they share the same code#.
Currently DTC83 shows only: "Reverse inhibit system (manual trans)(QDM)"
For the automatic transmission, that should be: "TCC CONTROL FEEDBACK FAULT (ODM)"
The error is actually in the "malf.csv" file and can be corrected easily with a simple text editor. I will change that in the next revision release of the files. Note that the 94 service manual does NOT show the description for DTC83 for automatic transmissions. I think that is an omission. The 95 manual does correctly show both descriptions for DTC83.
Attached is the corrected file. Replace your file with this one.
Currently DTC83 shows only: "Reverse inhibit system (manual trans)(QDM)"
For the automatic transmission, that should be: "TCC CONTROL FEEDBACK FAULT (ODM)"
The error is actually in the "malf.csv" file and can be corrected easily with a simple text editor. I will change that in the next revision release of the files. Note that the 94 service manual does NOT show the description for DTC83 for automatic transmissions. I think that is an omission. The 95 manual does correctly show both descriptions for DTC83.
Attached is the corrected file. Replace your file with this one.
Last edited by GaryDoug; Mar 26, 2016 at 05:36 PM.
Thread Starter
Prominent Member
Joined: Jul 2010
Posts: 1,519
From: Born on the Florida West Coast, now where can I retire?
Re: Scan9495: Free OBD1 scan app for 93/94/95 LT1
It's been pointed out to me that the 94 does not have a TCC PWM solenoid, so it's not an omission in the 94 manual. The 95 does have the TCC PWM solenoid. I will leave the description for both, since the 94 should not report a code for that solenoid in an automatic transmission car.
Registered User
Joined: Mar 1999
Posts: 2,068
From: Kernersville, NC
Re: Scan9495: Free OBD1 scan app for 93/94/95 LT1
Gary,
I was looking at a data log(in excel) that appears to have been created in Scan9495. I have a couple of questions.
The timestamp on the data, it's in hours:minutes:seconds correct?
If so, the amount of data collected every second is very impressive. Looks like you are getting around 40 engine parameter points every 142mS. Looks like around 3mS for each parameter. If I may ask, is this the mode of data communications that you were speaking of where you can grab several parameters at one time instead of requesting them one at a time? As in your post here?
https://www.camaroz28.com/forums/com...2/#post6954460
I just wanted to say nice work on the resolution. Is this speed possible on OBDII? ScanXL is nice, but it appears to be 6x slower on data collection than what you have developed. I guess we might be talking apples and oranges as one is OBDI and the the other is OBDII, but it would be nice to have the data collection speed that you have in your software.
I was looking at a data log(in excel) that appears to have been created in Scan9495. I have a couple of questions.
The timestamp on the data, it's in hours:minutes:seconds correct?
If so, the amount of data collected every second is very impressive. Looks like you are getting around 40 engine parameter points every 142mS. Looks like around 3mS for each parameter. If I may ask, is this the mode of data communications that you were speaking of where you can grab several parameters at one time instead of requesting them one at a time? As in your post here?
https://www.camaroz28.com/forums/com...2/#post6954460
I just wanted to say nice work on the resolution. Is this speed possible on OBDII? ScanXL is nice, but it appears to be 6x slower on data collection than what you have developed. I guess we might be talking apples and oranges as one is OBDI and the the other is OBDII, but it would be nice to have the data collection speed that you have in your software.
Last edited by ACE1252; Apr 2, 2016 at 11:29 AM.
Thread Starter
Prominent Member
Joined: Jul 2010
Posts: 1,519
From: Born on the Florida West Coast, now where can I retire?
Re: Scan9495: Free OBD1 scan app for 93/94/95 LT1
The timestamp on the data, it's in hours:minutes:seconds correct?
Correct
If so, the amount of data collected every second is very impressive. Looks like you are getting around 40 engine parameter points every 142mS. Looks like around 3mS for each parameter. If I may ask, is this the mode of data communications that you were speaking of where you can grab several parameters at one time instead of requesting them one at a time?
You can't ask for one piece of data with OBD1. It's "all" or nothing. You send a request for data and a bunch of values come back at once. Each pcm type is different. Some have separate sections for transmission, data controller, DTC's, etc. But they all have about 30 parameters or more per request.
Is this speed possible on OBDII? ScanXL is nice, but it appears to be 6x slower on data collection than what you have developed. I guess we might be talking apples and oranges as one is OBDI and the the other is OBDII, but it would be nice to have the data collection speed that you have in your software.
The GM OBD2 pcms have an extra non-mandated mode that allows multiple data per request. The scan tool has to set that up first, then request the string. But once it's set up, the requests can be done alone. I haven't done much with that yet. It would be faster per datum.
Registered User
Joined: Apr 2016
Posts: 5
Re: Scan9495: Free OBD1 scan app for 93/94/95 LT1
Not sure if this has been covered but i need some help. I have a 95 Impala SS with ob1. I build a rig to use the program with my car. The program reads everything in real time properly. Sensor voltage, temps, etc. I can reset the cel but its not pulling the codes. I know i have a active code being thrown that has to do with my fans. But nothing shows up in that window. Any input to why it isnt or what i may be doing wrong. Im using the ground and tan data wire on the odb-1 port which only has 3 pin outs