Can't read ABS codes
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From: El Torito, CA
According to my 91SM, the EBCM is located where your fourth photo shows; in the bottom of the center console, held up by a flat support bracket.
The visual inspection says to check instrument panel (IP) fuses: 8, 13 and 16. Also underhood fuse block fuses: 1 and 2.
Do you hear the ABS pump come on when you turn on the ignition?
From the SM:
The visual inspection says to check instrument panel (IP) fuses: 8, 13 and 16. Also underhood fuse block fuses: 1 and 2.
Do you hear the ABS pump come on when you turn on the ignition?
From the SM:
"Antilock" indicator is on and no codes are set.
When the ignition is first turn to "run", the EBCM goes through a self test. During this test the EBCM grounds the 'antilock' indicator at terminal 52 causing the indicator to light for several seconds. This acts as a bulb test for the indicator. During normal operation the main relay applies voltage to the EBCM and PMV assembly. If the EBCM should detect a fault, the main relay will de-energize causing the 'antilock' indicator to light since it is grounded through the main relay contacts.
Possible Causes -
* Open or short to ground in CKT 852 (EBCM to AntiLock indicator)
* Open in CKT 151 (main relay gnd), 650 (fuse 8 to MR & EBCM), 800 (ADL wire), 803 (EBCM gnd), or 1077 (EBCM to Antilock Diode).
* Open main relay coil.
* Brake fluid level low or open fluid level switch.
When the ignition is first turn to "run", the EBCM goes through a self test. During this test the EBCM grounds the 'antilock' indicator at terminal 52 causing the indicator to light for several seconds. This acts as a bulb test for the indicator. During normal operation the main relay applies voltage to the EBCM and PMV assembly. If the EBCM should detect a fault, the main relay will de-energize causing the 'antilock' indicator to light since it is grounded through the main relay contacts.
Possible Causes -
* Open or short to ground in CKT 852 (EBCM to AntiLock indicator)
* Open in CKT 151 (main relay gnd), 650 (fuse 8 to MR & EBCM), 800 (ADL wire), 803 (EBCM gnd), or 1077 (EBCM to Antilock Diode).
* Open main relay coil.
* Brake fluid level low or open fluid level switch.
for the help! 
Thread Starter
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Joined: Oct 2006
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Problem in paradise... 
Today I put in my new (used, but should be ok) ATE controller (ABS/EBCM-unit). Same problem - the ABS light is always on... :?
I made the car power-less by removing the battery, in hope of resetting the master computer, but that didn't help.
So now I don't know what to do. Apparently my car (1991) have Delco and not Teves, so then I will have to use a Tech 2 reader :?:
My idéa about replacing the front ABS sensors just by chance is not a good idéa because sensors cost about $300 each here in sweden. = not far from what I paid for the car... It'* a shame not to fix this car because it has only miled about 8700 US miles
Do you guys think that a Tech 2 reader will be able to read any codes - ie. is there a chance a pontiac service centre easily can figure out what is wrong? I can't spend a lot of money on this car, and I hate being left out in the hands of a mechanic telling me that "this and that has to be replaced" = expensive...
Any help deeply appreciated….
Ps: I just love the Internet! No matter what you are looking for, there are somebody out there with an answer – I just love the fact I found this forum!
Today I put in my new (used, but should be ok) ATE controller (ABS/EBCM-unit). Same problem - the ABS light is always on... :?
I made the car power-less by removing the battery, in hope of resetting the master computer, but that didn't help.
So now I don't know what to do. Apparently my car (1991) have Delco and not Teves, so then I will have to use a Tech 2 reader :?:
My idéa about replacing the front ABS sensors just by chance is not a good idéa because sensors cost about $300 each here in sweden. = not far from what I paid for the car... It'* a shame not to fix this car because it has only miled about 8700 US miles
Do you guys think that a Tech 2 reader will be able to read any codes - ie. is there a chance a pontiac service centre easily can figure out what is wrong? I can't spend a lot of money on this car, and I hate being left out in the hands of a mechanic telling me that "this and that has to be replaced" = expensive...
Any help deeply appreciated….
Ps: I just love the Internet! No matter what you are looking for, there are somebody out there with an answer – I just love the fact I found this forum!
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Joined: Apr 2004
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From: Three Oaks, Michigan
First off, Tech II does NOT work on OBD1 cars. It only works on OBD2 GM'*. I'm not sure if it works on the hybrid OBD1s, but if it does I will be surprised.
Second, ABS codes do not clear until the car has been driven past 30mph. And they won't clear under any circumstance unless the problem has been resolved.
Third, you need to find someone with an OTC scanner. Those will read the ABS codes on OBD1 systems. And I know this for a fact because I just did it today on my teves caddy. The OTCs are cheap and pretty easy to find at a dealer or whatever. Any GM dealer around here would have one... no idea about sweden; never been there. Just go there and ask if they have an OTC [4000? --padgett?] scanner for pre-93 GMs. If you go in there saying something smart like that, they often times won't go about ripping you off for some crap.
Second, ABS codes do not clear until the car has been driven past 30mph. And they won't clear under any circumstance unless the problem has been resolved.
Third, you need to find someone with an OTC scanner. Those will read the ABS codes on OBD1 systems. And I know this for a fact because I just did it today on my teves caddy. The OTCs are cheap and pretty easy to find at a dealer or whatever. Any GM dealer around here would have one... no idea about sweden; never been there. Just go there and ask if they have an OTC [4000? --padgett?] scanner for pre-93 GMs. If you go in there saying something smart like that, they often times won't go about ripping you off for some crap.
Thread Starter
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Hmm, what is a OBD1 and a OBD2 car? I’m not familiar with the term…
I have not tried driving with the car after the swap of the ABS unit, I will try that tomorrow! Thanks for the tip though!
OTC scanner… Whats that? It’* the fist time I heard of that… Is that a cheap device like the GM code reader?
I’m learning new things every day here!
I have not tried driving with the car after the swap of the ABS unit, I will try that tomorrow! Thanks for the tip though!
OTC scanner… Whats that? It’* the fist time I heard of that… Is that a cheap device like the GM code reader?
I’m learning new things every day here!
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From: Orlando, Florida
First GM car computers were the C3 (Computer Command Control - introed in 1981
Second Gen was the P4 seen in some 86s this used an 8192 baud serial data stream and is now referred to as the OBD I
OBD II standardised the format and the plugs across the manufacturers and came out in 1995
Note: engine lines that did not change when the new model came out often kept the older version past the intro of their replacement
Second Gen was the P4 seen in some 86s this used an 8192 baud serial data stream and is now referred to as the OBD I
OBD II standardised the format and the plugs across the manufacturers and came out in 1995
Note: engine lines that did not change when the new model came out often kept the older version past the intro of their replacement
Thread Starter
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Thx padget for the info!
Today I did a test drive to see if the ABS light went of, and it didn’t… :(
So now I guess my only option is to seek work shop with a “OTC 4000”… Thx for the help anyway!
Today I did a test drive to see if the ABS light went of, and it didn’t… :(
So now I guess my only option is to seek work shop with a “OTC 4000”… Thx for the help anyway!