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1995 Firebird LT1 Auto
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Discussion Starter · #1 ·
Hello, I just picked up a 1996 Firebird I’m fixing up. The Traction control and ABS lights come on moments after starting and driving. The lights are always off on restart and then come on once moving. The brakes seem to work worse until the ABS and TV lights come on.

many suggestions on where I can start?
Thanks in advance!
 

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1994 Firebird Formula 381ci LT1 / TH400+GV O/D
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Best approach is to read the codes from the EBTCM (electronic brake and traction control module). Scan 9495 software can do that. Can we assume “1996” is a typo, or did you buy another Firebird?


Most common problem is a faulty front wheel speed sensor. Sensor or harness connector can be dirty/corroded, or the wiring is damaged or loose. Unfortunately the sensor is embedded in the wheel bearing/spindle cartridge, and if defective, requires complete replacement of the cartridge. But that’s just speculation. Read the codes. Could also be as simple as a burned out center high mounted brake light. Neither of those problems would cause the braking to feel different until the lights come on.
 

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Discussion Starter · #3 ·
Best approach is to read the codes from the EBTCM (electronic brake and traction control module). Scan 9495 software can do that. Can we assume “1996” is a typo, or did you buy another Firebird?


Most common problem is a faulty front wheel speed sensor. Sensor or harness connector can be dirty/corroded, or the wiring is damaged or loose. Unfortunately the sensor is embedded in the wheel bearing/spindle cartridge, and if defective, requires complete replacement of the cartridge. But that’s just speculation. Read the codes. Could also be as simple as a burned out center high mounted brake light. Neither of those problems would cause the braking to feel different until the lights come on.
yea, 96 was a typo it’s a 95. I just bought a Bosch 1300 OBD I reader. I haven’t researched the Info you just sent me yet but I’m assuming my code reader won’t work?
 

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1994 Firebird Formula 381ci LT1 / TH400+GV O/D
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Not familiar with that specific scanner. Manufacture indicates “ABS…. codes…. for most 1996-2014 GM…. vehicles”. I believe the 95 ABS codes may be similar - ABS codes are not tied to a specific OBD standard. You need to try it to see if it can pull them. I believe Scan9495 will read the later year ABS codes. The issue may be where the correct pin is in the one-year (1995) only GM “OBD-1.5” 16-pin data link connector

Unfortunately, the author of Scan9495 (“GaryDoug”) would know the answer, but he abandoned this site because of issues with the site software. Shame, because he's an electrical engineer who knows everything there is about these cars.
 

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From the manufacturer, the Bosch 1300 is USB-1, USB-2, and CAN compatible.


The issue is whether there is any difference in the 95 and 96 EBTCM, since ABS and traction control are not necessarily defined by OBD.
 

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Discussion Starter · #7 ·
Thanks again for all the help. I’ll try it and post results. Otherwise form what I have researched, you should be able to test the wheel speed sensors by using a volt meter.
 

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Discussion Starter · #8 ·
From the manufacturer, the Bosch 1300 is USB-1, USB-2, and CAN compatible.


The issue is whether there is any difference in the 95 and 96 EBTCM, since ABS and traction control are not necessarily defined by OBD.
I haven’t had the time to try my scanner yet. Just also thinking, I do have a Chinese tech II, the Candi module doensnt really work most of the time but that wouldn’t be needed. would a Tech II work with a 95 OBD 1 by chance?
 

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1994 Firebird Formula 381ci LT1 / TH400+GV O/D
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Here's a review by our former resident scanning expert. He indicates it works on 1991 - 2013:

 

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Discussion Starter · #10 · (Edited)
Here's a review by our former resident scanning expert. He indicates it works on 1991 - 2013:

for some reason I’m getting no communication with vehicle error. Damn. The tool is being powered from the port so I’m sure it’s not a fuse. Another strange thing is the cigarette lighter doesn't work, but the fuse for cig/horn is fine and the horn works. Any ideas?
 

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Does the Tech-2 have or need a special cable for the OBD-1 PCM communicating through a 16-pin DLC? Or some sort of adapter? A true OBD-2 DLC uses pin 2 for “Serial Data - Class 2”, but the 95 DLC does not use that pin. I'm thinking (wild a** guess) the clone is trying to read that pin, but doesn’t know it should be using the “Serial Data - UART” from pin 9. Wish GaryDoug was still here. I'll see if I can get him to read through this thread and give me some hints.

I don't know anything about the Tech-2 (clone).

I know in 96 the same fuse that powers the cig lighter and horns also powers DLC pin 16. 95 should be similar, but I need to check the 95 factory service manual to verify, and I don't have access to that at the moment.

 
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Discussion Starter · #12 ·
Does the Tech-2 have or need a special cable for the OBD-1 PCM communicating through a 16-pin DLC? Or some sort of adapter? A true OBD-2 DLC uses pin 2 for “Serial Data - Class 2”, but the 95 DLC does not use that pin. I'm thinking (wild a** guess) the clone is trying to read that pin, but doesn’t know it should be using the “Serial Data - UART” from pin 9. Wish GaryDoug was still here. I'll see if I can get him to read through this thread and give me some hints.

I don't know anything about the Tech-2 (clone).

I know in 96 the same fuse that powers the cig lighter and horns also powers DLC pin 16. 95 should be similar, but I need to check the 95 factory service manual to verify, and I don't have access to that at the moment.

ok I gave up on my other scanners, using scan9495 with a cable I made and I finally have success. Not exactly sure how to work the software yet but it would appear I have an intermittent issues with the right front speed sensor. It says “22. Right front wheel speed sensor =0”.and when I was driving i noticed a delay with the right front speed sensor registering. So maybe this is why I have an abs and traction control error?Assuming the speed sensors are easily purchased as they are included in the front hub assembly?

any other suggestions on how I am to use this software to diagnose my issue?

thanks again!
 

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Yes on both accounts. Apart from data-logging, if you know specifically what you want to monitor, I suggest using the "live" graphing abilities Gary built in. It's much easier to see the data on a graph, especially when compared to another "identical" sensor than it is to look at one little cell on the screen. The "actuators" page is pretty handy too. Do always look up the DTC in the Factory Service Manual to verify the text of the error is correct, and obviously, follow the diagnostic flow chart for the specific DTC. Feel free to click around in Scan9495, you're not going to hurt anything, it only reads data. Apart from clearing DTCs, it does not write anything to the PCM.
 

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1994 Firebird Formula 381ci LT1 / TH400+GV O/D
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It says “22. Right front wheel speed sensor =0”.and when I was driving i noticed a delay with the right front speed sensor registering. So maybe this is why I have an abs and traction control error?
Did you look in the 1995 factory service manual, page 5E2-60? It clearly shows that this code disables ABS and TCS. The description also shows possible causes, not all of which are a faulty wheel sensor. The manual is a good source of this kind of info. That's why Gary made them available to us for FREE download.
 

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Discussion Starter · #15 ·
Did you look in the 1995 factory service manual, page 5E2-60? It clearly shows that this code disables ABS and TCS. The description also shows possible causes, not all of which are a faulty wheel sensor. The manual is a good source of this kind of info. That's why Gary made them available to us for FREE download.
thanks for this. I just had a look at this in the manual. Looks like the right front sensor is a potential culprit. Need to measure resistance to verify. Further to that, it’s something with the wiring or EBTCM.
I searched in the manual for a location of the EBTCM module. People on a google search say under driver side dash. Do you know if this is accurate?

I like that I’m ticking off all the issues one at a time. Great forum and people! Thanks again for the spoon feeding.
 

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Component locations are shown on page 5E2-9.

”above driver side kick panel”
 

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Discussion Starter · #17 ·
Component locations are shown on page 5E2-9.

”above driver side kick panel”
I have fantastic news. It was the front right speed sensor. All working great now! Super pumped I built a cable and had success with scan 9495 with windows 10. Thanks again for all the awesome advise. Now I’m on to the next thing.
 

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1994 Firebird Formula 381ci LT1 / TH400+GV O/D
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You replaced the right front wheel speed sensor, an integral part of the complete spindle/bearing/sensor assembly?
 

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OK. Just wanted to be clear. When we have a problem that has been resolved, we moved the thread to "Resolved Issues". Hopefully, someone with a similar problem will do a "search" and find your solution.
 
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