ABS Code C0121
Thread Starter
Burning Brakes
Joined: Oct 2009
Posts: 960
Likes: 61
From: oswego ny
ABS Code C0121
I had just pulled out my Pioneer sterio H.U. and that was working and i put in a new Alpine unit and wired in a PAC-TR7 that is needed to get to all the settings in the H.U. -(shows car ebrake on)
Now after starting car up and less than a min later the A.B.S. and trac light came on and said service... And ive never had this happen before.. It has a code of C0121.
Im convinced it is something i did or possible that PAC unit. ? You wouldnt think it would but ?...oh, mine is a 06 vert..
ANY idea guys..
Now after starting car up and less than a min later the A.B.S. and trac light came on and said service... And ive never had this happen before.. It has a code of C0121.
Im convinced it is something i did or possible that PAC unit. ? You wouldnt think it would but ?...oh, mine is a 06 vert..
ANY idea guys..
Last edited by carls2004; Jul 12, 2017 at 05:26 PM.
Le Mans Master
Joined: Mar 2002
Posts: 8,466
Likes: 51
St. Jude Donor '17
I had just pulled out my Pioneer sterio H.U. and that was working and i put in a new Alpine unit and wired in a PAC-TR7 that is needed to get to all the settings in the H.U. -(shows car ebrake on)
Now after starting car up and less than a min later the A.B.S. and trac light came on and said service... And ive never had this happen before.. It has a code of C0121.
Im convinced it is something i did or possible that PAC unit. ? You wouldnt think it would but ?...oh, mine is a 06 vert..
ANY idea guys..
Now after starting car up and less than a min later the A.B.S. and trac light came on and said service... And ive never had this happen before.. It has a code of C0121.
Im convinced it is something i did or possible that PAC unit. ? You wouldnt think it would but ?...oh, mine is a 06 vert..
ANY idea guys..
If it turns out to be the ebcm itself i have one off a 2012
with out a techII or clone you cant really test the wheel speed sensors or connectors are operating correctly.
Last edited by Got uid0; Jul 12, 2017 at 09:14 PM.
Thread Starter
Burning Brakes
Joined: Oct 2009
Posts: 960
Likes: 61
From: oswego ny
check the ebcm fuses under the hood. Since you were doing some wiring work its seems more likely you caused something with the wiring to throw a fuse.
If it turns out to be the ebcm itself i have one off a 2012
with out a techII or clone you cant really test the wheel speed sensors or connectors are operating correctly.
If it turns out to be the ebcm itself i have one off a 2012
with out a techII or clone you cant really test the wheel speed sensors or connectors are operating correctly.
Is there more than the two or any relay i didnt see. ??????????..
Very weird never had a issue.. Put in deck. fire it up, and light's and code
Just still makes me feel i did something but can figure out how...
My coworker has the snap on unit which i think can do what techII doe's. And for what code is there, seems funny it be wheel sensor if it is something i didnt do.??
Oh almost forgot... I was careful when i did the deck and i didnt unhook the battery.. BUT right after light/code came on- i drove car for 4 miles, and i noticed that inside volt meter read battery wasnt charging.. then it slowly climbs up above 13... then was back down a few times... And i did have doors open during install..
Last edited by carls2004; Jul 12, 2017 at 09:58 PM. Reason: info
Le Mans Master
Joined: Mar 2002
Posts: 8,466
Likes: 51
St. Jude Donor '17
Yea i checked the two fuses i could fine. One was a mini and other i think they call J fuse. I checked that by just swapping out..
Is there more than the two or any relay i didnt see. ??????????..
Very weird never had a issue.. Put in deck. fire it up, and light's and code
Just still makes me feel i did something but can figure out how...
My coworker has the snap on unit which i think can do what techII doe's. And for what code is there, seems funny it be wheel sensor if it is something i didnt do.??
Oh almost forgot... I was careful when i did the deck and i didnt unhook the battery.. BUT right after light/code came on- i drove car for 4 miles, and i noticed that inside volt meter read battery wasnt charging.. then it slowly climbs up above 13... then was back down a few times... And i did have doors open during install..
Is there more than the two or any relay i didnt see. ??????????..
Very weird never had a issue.. Put in deck. fire it up, and light's and code
Just still makes me feel i did something but can figure out how...
My coworker has the snap on unit which i think can do what techII doe's. And for what code is there, seems funny it be wheel sensor if it is something i didnt do.??
Oh almost forgot... I was careful when i did the deck and i didnt unhook the battery.. BUT right after light/code came on- i drove car for 4 miles, and i noticed that inside volt meter read battery wasnt charging.. then it slowly climbs up above 13... then was back down a few times... And i did have doors open during install..
It may be interfering with the wiring on the circuit causing the fault.
Possible that you wired that wrong or have a bad ground?
Last edited by Got uid0; Jul 12, 2017 at 10:25 PM.
Thread Starter
Burning Brakes
Joined: Oct 2009
Posts: 960
Likes: 61
From: oswego ny
Hard to say, disconnect the battery for 10 minutes and cross fingers. Charge the battery to rule that out or back out the wiring install. That pac unit is to fake out the system that the brake is on so you can play videos correct?
It may be interfering with the wiring on the circuit causing the fault.
Possible that you wired that wrong or have a bad ground?
https://www.youtube.com/watch?v=l4QyQRTtNFM
It may be interfering with the wiring on the circuit causing the fault.
Possible that you wired that wrong or have a bad ground?
https://www.youtube.com/watch?v=l4QyQRTtNFM
Im gonna try this in order then pull deck if all fails..
1=disconnect battery and do hard reset.
2= charge battery.
3= reverse on my install.
There was a light green wire off old pioneer unit that attached to the OS-2BOSE that i cut off and it didnt get anything hooked back up to it. ? and that was pioneers brake signal..
And now i have a microBypass that i can try in place of the PAC-TR7 that came in late today...
The pac unit i would of skipped as i wont be watching video.. BUT i was told that you cant even get into alot of the Alpine deck settings without it... which i thought was stupid on Alpines half.
Last edited by carls2004; Jul 12, 2017 at 10:44 PM.
Thread Starter
Burning Brakes
Joined: Oct 2009
Posts: 960
Likes: 61
From: oswego ny
Rechecked wiring and also put in the microBypass in place of the PAC unit...... Same issue code C0121.
When i went to rewire and check i forgot that the ACC takes awhile before it kicks off and while i was cutting out the Pac-tr7 , i hit ground and chimes went off..
Possible i might of done this on orig install but dont seem it would set abs code unless i blew a fuse.. ???????????....
I thought maybe it did something to the OS2-BOSE that is in veh to keep on star if needed and chimes but all seems ok with it.. ???
When i went to rewire and check i forgot that the ACC takes awhile before it kicks off and while i was cutting out the Pac-tr7 , i hit ground and chimes went off..
Possible i might of done this on orig install but dont seem it would set abs code unless i blew a fuse.. ???????????....
I thought maybe it did something to the OS2-BOSE that is in veh to keep on star if needed and chimes but all seems ok with it.. ???
Last edited by carls2004; Jul 13, 2017 at 05:19 PM.
Le Mans Master
Joined: Mar 2002
Posts: 8,466
Likes: 51
St. Jude Donor '17
Rechecked wiring and also put in the microBypass in place of the PAC unit...... Same issue code C0121.
When i went to rewire and check i forgot that the ACC takes awhile before it kicks off and while i was cutting out the Pac-tr7 , i hit ground and chimes went off..
Possible i might of done this on orig install but dont seem it would set abs code unless i blew a fuse.. ???????????....
I thought maybe it did something to the OS2-BOSE that is in veh to keep on star if needed and chimes but all seems ok with it.. ???
When i went to rewire and check i forgot that the ACC takes awhile before it kicks off and while i was cutting out the Pac-tr7 , i hit ground and chimes went off..
Possible i might of done this on orig install but dont seem it would set abs code unless i blew a fuse.. ???????????....
I thought maybe it did something to the OS2-BOSE that is in veh to keep on star if needed and chimes but all seems ok with it.. ???
I would double check every abs fuse under the hood and anything in the foot well. If the code is set hard you will need a techII type tool to reset it.
Could be possible that you popped a fuse or damaged EBCM touching ground on the brake wire circuit.
Thread Starter
Burning Brakes
Joined: Oct 2009
Posts: 960
Likes: 61
From: oswego ny
You did not disconnect the battery?
I would double check every abs fuse under the hood and anything in the foot well. If the code is set hard you will need a techII type tool to reset it.
Could be possible that you popped a fuse or damaged EBCM touching ground on the brake wire circuit.
I would double check every abs fuse under the hood and anything in the foot well. If the code is set hard you will need a techII type tool to reset it.
Could be possible that you popped a fuse or damaged EBCM touching ground on the brake wire circuit.
Before install i saw there was a wire on tunnel that attaches to ebrake but i did put test light on that connector to see if any voltage but none so i figured it must be ? ground ? but if i remember right i traced the wire and it ended up going no where.(was from previous radio install) Like it may have been for ?.
Ive checked All fuses twice now and test fine. So i then had coworker put on a snapon scanner which can do pretty much what the techII can. and he erased it and it will pop up FAST AS you start it...
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Le Mans Master
Joined: Mar 2002
Posts: 8,466
Likes: 51
St. Jude Donor '17
your pac wire was setup to interact with the brake system and if it was wired incorrectly it does feed power to the circuit.
If it were me i would either pull the radio fuse and test after clearing the code or completely restore everything exactly back to prior to the problems.
You have to determine if you have a damaged ebcm.
If it were me i would either pull the radio fuse and test after clearing the code or completely restore everything exactly back to prior to the problems.
You have to determine if you have a damaged ebcm.
Thread Starter
Burning Brakes
Joined: Oct 2009
Posts: 960
Likes: 61
From: oswego ny
your pac wire was setup to interact with the brake system and if it was wired incorrectly it does feed power to the circuit.
If it were me i would either pull the radio fuse and test after clearing the code or completely restore everything exactly back to prior to the problems.
You have to determine if you have a damaged ebcm.
If it were me i would either pull the radio fuse and test after clearing the code or completely restore everything exactly back to prior to the problems.
You have to determine if you have a damaged ebcm.
Last edited by carls2004; Jul 16, 2017 at 11:07 AM.
Le Mans Master
Joined: Mar 2002
Posts: 8,466
Likes: 51
St. Jude Donor '17
Did pulling the radio fuse help as a test?
Thread Starter
Burning Brakes
Joined: Oct 2009
Posts: 960
Likes: 61
From: oswego ny
Didnt get back to car this weekend.. frustrated ..
Gonna try to erase code again and try to see if i can get battery disconnected fast enough after i erase it... Then do a full discharge by removing battery cables and hold together for 10-15 min..
If code pop's right back on i guess i gotta try to get to the AB.S. UNIT and test ground's and Voltage to the unit..
Last edited by carls2004; Jul 16, 2017 at 08:27 PM.
Thread Starter
Burning Brakes
Joined: Oct 2009
Posts: 960
Likes: 61
From: oswego ny
Been driving the car with the C0121 code as im pretty sure the EBCM is bad..
But now when i started car this morning the ebrake light is on now and service veh. And i lost alot of steering assist...
So i hooked up scanner and it says, Cant communicate with A.B.S. and also the E.C.M. say's that it cant communicate with it. And i have code of U0121.
So i rechecked fuses (good) and also looked for elect conn plug below seat and or in left kick panel as i know the C5 has issue's there. But all seem good.
So since i was at work and little time i did crawl under veh and got conn unhooked at abs unit and i knew that there was 2 wires ? that should have battery voltage and it doe;s....
So i guess im asking do you think it is deff the EBCM
But now when i started car this morning the ebrake light is on now and service veh. And i lost alot of steering assist...
So i hooked up scanner and it says, Cant communicate with A.B.S. and also the E.C.M. say's that it cant communicate with it. And i have code of U0121.
So i rechecked fuses (good) and also looked for elect conn plug below seat and or in left kick panel as i know the C5 has issue's there. But all seem good.
So since i was at work and little time i did crawl under veh and got conn unhooked at abs unit and i knew that there was 2 wires ? that should have battery voltage and it doe;s....
So i guess im asking do you think it is deff the EBCM
Last edited by carls2004; Aug 21, 2017 at 03:10 PM.
Instructor
Joined: Aug 2008
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Thread Starter
Burning Brakes
Joined: Oct 2009
Posts: 960
Likes: 61
From: oswego ny
@carls2004 Did you figure it out?