random failure with defaut U2100
07-01-2018, 05:15 PM
#1
random failure with defaut U2100
HI
Got a C6 2005 BVA4
and I'm in France :p
Got a random failure with defaut U2100,( saw on my ODB phone program for free... can be lots of things...
got any idea to check and how to check ?
and with this got also got some gauge which are going to 0 as if I was not driving, also cut A/C only got battery still on 13... others are going up and down all 3 or just 2 .... last time I also got like if the ABS was régulating all 4 wheels together.....
And by the way BVA stay in 3rd
After a small erase can keep 50 miles or 500 miles with no default....try to change ABS sensor, Battery, Alternator still come back...*
thanks for your help :
Got a C6 2005 BVA4
and I'm in France :p
Got a random failure with defaut U2100,( saw on my ODB phone program for free... can be lots of things...
got any idea to check and how to check ?
and with this got also got some gauge which are going to 0 as if I was not driving, also cut A/C only got battery still on 13... others are going up and down all 3 or just 2 .... last time I also got like if the ABS was régulating all 4 wheels together.....
And by the way BVA stay in 3rd
After a small erase can keep 50 miles or 500 miles with no default....try to change ABS sensor, Battery, Alternator still come back...
*thanks for your help :
07-02-2018, 06:32 PM
#2
U2100 Controller Area Network (CAN) Bus Communication ESC, BCM, EBCM, TCM
Most of the time the code will come from a bad connecting on the one of the Connectors to a main module, but can come from a module either going bad, or the power dropping too low to that module to time out isntead.
So we are taking about a loss of communication from the BCM to the ESC (f55 module), the EBCM(abs unit), and the TCM (module just behind the ECM module in the fender well area on the passanger side since this is a 2005 A4 trans car).
So starting with the BCM connector and moving outwards one connector at a time, would pull the cam lock connectors to give them a good spray electrical contract cleaner cleaning and reconnected them. Also, pull the battery and on the passenger fender side area cubby just about middle level of where the battery was located , your going to see two square block connectors as well. Pull these connectors to spray clean them too. The one with the more wires is the J184 connector, hence trans to Motor connectors, and they can have problems from time to time as well since acid from the battery fumes as the battery vents, can cause corrosion problems in these two connectors.
Also, since you need to pull the ECM to get to the TCM, good idea to clean the ECM connectors as well.
ECM/TCM location, and the blue connector you see in the lower photo is the TCM connector since the module is bolted to the back side of the plastic piece behind the ECM.
To get to the ECM and BCM, pull the center pins out of the plastic fasteners of the lower back passenger front fender well liner, then you will have three more bolts on the bottom of the fender liner panel to remove the panel.
As for all the connectors, they are all cam arm locked, so you have to cam the lock levers straight out on the connector to disegage the connector locks. Once the the arm is unlocked, pull the connectors straight out, not twisted of cocked to one side isntead.
Once you are sure that the connectors are not the problem, then put a Tech II on the car and start checking voltages of each modules (should be around the 14v range). since we know that the connectors are good, then if you do find a low voltage on one of the modules, then time to double check that modules ground point to the frame next.
Also from the start before you even get knee deep in module connectors, check the charging system to make sure it fine to start with.
The alternator should have 14.7 volts with the car idling, A/C and lights off, and if it lower than this, start here,
https://www.corvetteforum.com/forums...nator-fix.html
As for the rest of the charging system and is voltage check areas,
https://www.corvetteforum.com/forums...intenance.html
So short bus with the A/C off, and the car idling,
Should have 14.7 at the altenator, 14.5 at the battery and fuse block terminal, 14.1~3 on the DIC (telling you the voltage of the ECM), and then will need a tech II to check the voltage of the rest of the modules.
Note, power goes from the engine fuse block, to the BCM, then to the ECM. So if you do have 14.5V at the engine fuse block, but only 12ish at the DIC/ECM, bank that the problem is the BCM/BCM connector.
One last thing, and the large blue 20 amp fuse center of the BCM is the GM land bus fuse. So as you cleaning the BCM connectors, make sure to pull the fuses on the BCM to clean them as well.
Most of the time the code will come from a bad connecting on the one of the Connectors to a main module, but can come from a module either going bad, or the power dropping too low to that module to time out isntead.
So we are taking about a loss of communication from the BCM to the ESC (f55 module), the EBCM(abs unit), and the TCM (module just behind the ECM module in the fender well area on the passanger side since this is a 2005 A4 trans car).
So starting with the BCM connector and moving outwards one connector at a time, would pull the cam lock connectors to give them a good spray electrical contract cleaner cleaning and reconnected them. Also, pull the battery and on the passenger fender side area cubby just about middle level of where the battery was located , your going to see two square block connectors as well. Pull these connectors to spray clean them too. The one with the more wires is the J184 connector, hence trans to Motor connectors, and they can have problems from time to time as well since acid from the battery fumes as the battery vents, can cause corrosion problems in these two connectors.
Also, since you need to pull the ECM to get to the TCM, good idea to clean the ECM connectors as well.
ECM/TCM location, and the blue connector you see in the lower photo is the TCM connector since the module is bolted to the back side of the plastic piece behind the ECM.
To get to the ECM and BCM, pull the center pins out of the plastic fasteners of the lower back passenger front fender well liner, then you will have three more bolts on the bottom of the fender liner panel to remove the panel.
As for all the connectors, they are all cam arm locked, so you have to cam the lock levers straight out on the connector to disegage the connector locks. Once the the arm is unlocked, pull the connectors straight out, not twisted of cocked to one side isntead.
Once you are sure that the connectors are not the problem, then put a Tech II on the car and start checking voltages of each modules (should be around the 14v range). since we know that the connectors are good, then if you do find a low voltage on one of the modules, then time to double check that modules ground point to the frame next.
Also from the start before you even get knee deep in module connectors, check the charging system to make sure it fine to start with.
The alternator should have 14.7 volts with the car idling, A/C and lights off, and if it lower than this, start here,
https://www.corvetteforum.com/forums...nator-fix.html
As for the rest of the charging system and is voltage check areas,
https://www.corvetteforum.com/forums...intenance.html
So short bus with the A/C off, and the car idling,
Should have 14.7 at the altenator, 14.5 at the battery and fuse block terminal, 14.1~3 on the DIC (telling you the voltage of the ECM), and then will need a tech II to check the voltage of the rest of the modules.
Note, power goes from the engine fuse block, to the BCM, then to the ECM. So if you do have 14.5V at the engine fuse block, but only 12ish at the DIC/ECM, bank that the problem is the BCM/BCM connector.
One last thing, and the large blue 20 amp fuse center of the BCM is the GM land bus fuse. So as you cleaning the BCM connectors, make sure to pull the fuses on the BCM to clean them as well.
Last edited by Dano523; 07-02-2018 at 06:52 PM.
The following users liked this post:
wagram (07-03-2018)
07-02-2018, 06:50 PM
#3
To add, if after all this, find out that the problem is in say one of the Modules itself (ECBM or BCM), Don't Panic.
Since the problem is an intermediate problem with the module, could just be a cold solder joint on one of the modules boards.
Hence the boards can be pulled so you can just re-solder the bad cold solder joint on the board to resolve the problem instead (without having to replace the entire module and SPS firmware reflash the new module to the car as well)
Since the problem is an intermediate problem with the module, could just be a cold solder joint on one of the modules boards.
Hence the boards can be pulled so you can just re-solder the bad cold solder joint on the board to resolve the problem instead (without having to replace the entire module and SPS firmware reflash the new module to the car as well)
The following users liked this post:
wagram (07-03-2018)
07-03-2018, 04:14 AM
#4
To add, if after all this, find out that the problem is in say one of the Modules itself (ECBM or BCM), Don't Panic.
Since the problem is an intermediate problem with the module, could just be a cold solder joint on one of the modules boards.
Hence the boards can be pulled so you can just re-solder the bad cold solder joint on the board to resolve the problem instead (without having to replace the entire module and SPS firmware reflash the new module to the car as well)
Since the problem is an intermediate problem with the module, could just be a cold solder joint on one of the modules boards.
Hence the boards can be pulled so you can just re-solder the bad cold solder joint on the board to resolve the problem instead (without having to replace the entire module and SPS firmware reflash the new module to the car as well)
I bought a new alternator this one ... but I maybe made a mistake cause got a BVA so maybe the problem is there https://www.rockauto.com/fr/moreinfo...432739&jsn=459
I should have order this one instead no : https://www.rockauto.com/fr/moreinfo...432739&jsn=458 ?
07-03-2018, 05:54 PM
#5
When your cleaning the BCM connectors, double check the amount of slack on the wire harness looms.
The wire loom that comes back under the passanger floor area can be on the tight side, and this can cause problems with passengers pushing too hard on the carpet to cause problem with the connector at the BCM. If you find the wire loom too taunt on that comes back under the passenger side under the carpet, pull the passenger carpet up enough to get to the strap point of the loom to pull some extra slack on the wire loom bundle of wires for that connector in the BCM.
The wire loom that comes back under the passanger floor area can be on the tight side, and this can cause problems with passengers pushing too hard on the carpet to cause problem with the connector at the BCM. If you find the wire loom too taunt on that comes back under the passenger side under the carpet, pull the passenger carpet up enough to get to the strap point of the loom to pull some extra slack on the wire loom bundle of wires for that connector in the BCM.
Last edited by Dano523; 07-03-2018 at 05:56 PM.
The following users liked this post:
wagram (07-03-2018)
07-03-2018, 06:09 PM
#6
Also to point out, both the C184 connector (to the side of the battery)is on that side of the car, as well as the BCM and TCM connectors as well.
As for the alternators you list, both are for A6 trans, since they have the pulley clutch. The M6 trans cars will have a solid pulley without clutch.
As for if the alternator is the problem, in the battery manitaince Link, your first check is to check the output of the alternator with the car idling/ac off, and should be 14.7 volt from the post on the back of the alternator under the rubber boot, to the body of the alternator using a multi meter. Next reading is at the battery terminal, which should be 14.5 volts, 14.5 volts from the fuse block terminal to either the battery ground, or the body of the alternator as ground, and the final check is the DIC which should show 14.3~14.1 volts (voltage of the ECM). If you have the 14.7 volt and 14.5 volts at the battery/fuse block, but way, way less voltage on the DIV voltage (not 14.1~14.3), then means a problem at either the red BCM connector, or a problem at the power connector to the ECM or its grounding point to the frame isntead.
If your looking for ground points to the frame, post #7
https://www.corvetteforum.com/forums...locations.html
As for the alternators you list, both are for A6 trans, since they have the pulley clutch. The M6 trans cars will have a solid pulley without clutch.
As for if the alternator is the problem, in the battery manitaince Link, your first check is to check the output of the alternator with the car idling/ac off, and should be 14.7 volt from the post on the back of the alternator under the rubber boot, to the body of the alternator using a multi meter. Next reading is at the battery terminal, which should be 14.5 volts, 14.5 volts from the fuse block terminal to either the battery ground, or the body of the alternator as ground, and the final check is the DIC which should show 14.3~14.1 volts (voltage of the ECM). If you have the 14.7 volt and 14.5 volts at the battery/fuse block, but way, way less voltage on the DIV voltage (not 14.1~14.3), then means a problem at either the red BCM connector, or a problem at the power connector to the ECM or its grounding point to the frame isntead.
If your looking for ground points to the frame, post #7
https://www.corvetteforum.com/forums...locations.html
07-03-2018, 06:22 PM
#7
Also to point out, both the C184 connector (to the side of the battery)is on that side of the car, as well as the BCM and TCM connectors as well.
As for the alternators you list, both are for A6 trans, since they have the pulley clutch. The M6 trans cars will have a solid pulley without clutch.
As for if the alternator is the problem, in the battery manitaince Link, your first check is to check the output of the alternator with the car idling/ac off, and should be 14.7 volt from the post on the back of the alternator under the rubber boot, to the body of the alternator using a multi meter. Next reading is at the battery terminal, which should be 14.5 volts, 14.5 volts from the fuse block terminal to either the battery ground, or the body of the alternator as ground, and the final check is the DIC which should show 14.3~14.1 volts (voltage of the ECM). If you have the 14.7 volt and 14.5 volts at the battery/fuse block, but way, way less voltage on the DIV voltage (not 14.1~14.3), then means a problem at either the red BCM connector, or a problem at the power connector to the ECM or its grounding point to the frame isntead.
If your looking for ground points to the frame, post #7
https://www.corvetteforum.com/forums...locations.html
As for the alternators you list, both are for A6 trans, since they have the pulley clutch. The M6 trans cars will have a solid pulley without clutch.
As for if the alternator is the problem, in the battery manitaince Link, your first check is to check the output of the alternator with the car idling/ac off, and should be 14.7 volt from the post on the back of the alternator under the rubber boot, to the body of the alternator using a multi meter. Next reading is at the battery terminal, which should be 14.5 volts, 14.5 volts from the fuse block terminal to either the battery ground, or the body of the alternator as ground, and the final check is the DIC which should show 14.3~14.1 volts (voltage of the ECM). If you have the 14.7 volt and 14.5 volts at the battery/fuse block, but way, way less voltage on the DIV voltage (not 14.1~14.3), then means a problem at either the red BCM connector, or a problem at the power connector to the ECM or its grounding point to the frame isntead.
If your looking for ground points to the frame, post #7
https://www.corvetteforum.com/forums...locations.html
07-04-2018, 06:48 AM
#8
Not really, since the car is already struggling with the 145amp alternator only putting out about 14 amps at idle, and the 110a is only putting out about 10 amps at idle instead.
Truth is, if you need to swap alternators, then forgo the oem valeo 145 amp unit, and find localy/ have someone import one of the Billet alternators to you to install instead.
The oem are 3 pole/phase alternators, and the reason that they put out such a low amperage (only about 10%) at idle to begin with.
The billet alternators are 6 pole/phase, and put out about 45 amps at idle isntead.
Hence it not the max amperage when its fully spun up that really matters on the C6, but what is needed of the alternator to keep up with the car when you are sitting at a stop light with the a/c on instead. With the A/c on, or the motor hot enough to turn the fan on instead, the raditor fan starts at about 12 amps at it lower setting, ramps up to about 16 amps at it high setting, and with the cars other electrical needs, even the 145a max/14amps at idle, is not able to keep up with the car demand when the motor is idling at say a stop light.
Check to see if someone local already has 6 pole/phase Mechman Billet-Tech in stock so you don't have to play the export game out of the states, but if needed, you can check with a few of the USA vendors to see who can sell and export you one instead.
https://www.corvetteforum.com/forums...w-pricing.html
Also, if the car has an automatic trans, make sure that the pulley on the alternator has a clutch. If you order in billet tech from the states, let them know and they will install the pulley with clutch on the alternator. The clutch is a one way device that has the alternator spinning up with the engine, but allow is to free wheel when the revs are dropping, so it puts less drag on the motor belt system as the revs are dropping, to allow the trans to shift correctly instead.
Truth is, if you need to swap alternators, then forgo the oem valeo 145 amp unit, and find localy/ have someone import one of the Billet alternators to you to install instead.
The oem are 3 pole/phase alternators, and the reason that they put out such a low amperage (only about 10%) at idle to begin with.
The billet alternators are 6 pole/phase, and put out about 45 amps at idle isntead.
Hence it not the max amperage when its fully spun up that really matters on the C6, but what is needed of the alternator to keep up with the car when you are sitting at a stop light with the a/c on instead. With the A/c on, or the motor hot enough to turn the fan on instead, the raditor fan starts at about 12 amps at it lower setting, ramps up to about 16 amps at it high setting, and with the cars other electrical needs, even the 145a max/14amps at idle, is not able to keep up with the car demand when the motor is idling at say a stop light.
Check to see if someone local already has 6 pole/phase Mechman Billet-Tech in stock so you don't have to play the export game out of the states, but if needed, you can check with a few of the USA vendors to see who can sell and export you one instead.
https://www.corvetteforum.com/forums...w-pricing.html
Also, if the car has an automatic trans, make sure that the pulley on the alternator has a clutch. If you order in billet tech from the states, let them know and they will install the pulley with clutch on the alternator. The clutch is a one way device that has the alternator spinning up with the engine, but allow is to free wheel when the revs are dropping, so it puts less drag on the motor belt system as the revs are dropping, to allow the trans to shift correctly instead.
07-12-2018, 05:19 AM
#9
Not really, since the car is already struggling with the 145amp alternator only putting out about 14 amps at idle, and the 110a is only putting out about 10 amps at idle instead.
Truth is, if you need to swap alternators, then forgo the oem valeo 145 amp unit, and find localy/ have someone import one of the Billet alternators to you to install instead.
The oem are 3 pole/phase alternators, and the reason that they put out such a low amperage (only about 10%) at idle to begin with.
The billet alternators are 6 pole/phase, and put out about 45 amps at idle isntead.
Hence it not the max amperage when its fully spun up that really matters on the C6, but what is needed of the alternator to keep up with the car when you are sitting at a stop light with the a/c on instead. With the A/c on, or the motor hot enough to turn the fan on instead, the raditor fan starts at about 12 amps at it lower setting, ramps up to about 16 amps at it high setting, and with the cars other electrical needs, even the 145a max/14amps at idle, is not able to keep up with the car demand when the motor is idling at say a stop light.
Check to see if someone local already has 6 pole/phase Mechman Billet-Tech in stock so you don't have to play the export game out of the states, but if needed, you can check with a few of the USA vendors to see who can sell and export you one instead.
https://www.corvetteforum.com/forums...w-pricing.html
Also, if the car has an automatic trans, make sure that the pulley on the alternator has a clutch. If you order in billet tech from the states, let them know and they will install the pulley with clutch on the alternator. The clutch is a one way device that has the alternator spinning up with the engine, but allow is to free wheel when the revs are dropping, so it puts less drag on the motor belt system as the revs are dropping, to allow the trans to shift correctly instead.
Truth is, if you need to swap alternators, then forgo the oem valeo 145 amp unit, and find localy/ have someone import one of the Billet alternators to you to install instead.
The oem are 3 pole/phase alternators, and the reason that they put out such a low amperage (only about 10%) at idle to begin with.
The billet alternators are 6 pole/phase, and put out about 45 amps at idle isntead.
Hence it not the max amperage when its fully spun up that really matters on the C6, but what is needed of the alternator to keep up with the car when you are sitting at a stop light with the a/c on instead. With the A/c on, or the motor hot enough to turn the fan on instead, the raditor fan starts at about 12 amps at it lower setting, ramps up to about 16 amps at it high setting, and with the cars other electrical needs, even the 145a max/14amps at idle, is not able to keep up with the car demand when the motor is idling at say a stop light.
Check to see if someone local already has 6 pole/phase Mechman Billet-Tech in stock so you don't have to play the export game out of the states, but if needed, you can check with a few of the USA vendors to see who can sell and export you one instead.
https://www.corvetteforum.com/forums...w-pricing.html
Also, if the car has an automatic trans, make sure that the pulley on the alternator has a clutch. If you order in billet tech from the states, let them know and they will install the pulley with clutch on the alternator. The clutch is a one way device that has the alternator spinning up with the engine, but allow is to free wheel when the revs are dropping, so it puts less drag on the motor belt system as the revs are dropping, to allow the trans to shift correctly instead.
For the alternator ask to Mechman can ship it but also told me about a cable which is going directly to the BCM .... do not understand what is it for ..if any one got an idea*
