Faslane

I have a 09 base automatic 19k miles. known the car its whole life, no accidents or issues, It is my wife's 2nd car and she does not drive it much but it gets started and moved around the shop weekly to move cars around make some room or to get another car out. I started having the no start situation where you push start and the gauges sweep then blank with only the check engine light symbol showing and no start. I googled and learned a lot, I found and cleaned all the grounds, battery checked and replaced checked all the connection while battery out and eve took the tray out to check cables, blue connectors at BCM, all the easy free things to check, I came to my opinion of replacing the BCM, I went to the dealership and bought a brand new BCM. I have a Tech 2 and a membership at tis web and also have Tech 2 Win using my MDI 2 as pass through. Got it home installed set up BCM, Crank relearn, unlocked radio ect. started great. All went great except I could not calibrate the brake switch, I tried everything, the brake lights were on all the time as well, It also said the service warnings on dash for suspension and traction systems, I have read tons of forum threads about this issue and had a good feeling it was a connector somewhere, cleaned and checked all connectors or connections that are usually the culprit, no change. I then ordered a brake switch off ebay even tho I had a feeling it was not the issue from all the information from all the threads I have read. I installed the brake switch from ebay turned ignition on fired up the tech 2 went to calibrate and no deal, same as before. I went another month or so reading and learning and nothing changed the situation, I even tried through tis web with the mdi 2 an no dice. One day I went to advance auto parts to get something for another car and thought what the heck ordered another brake switch for her vette. It was the BWD brand, unhooked the negative side of the battery installed that brake switch I powered up turned key on, perfect, showed hit brake to start on dash, pushed the brake started the car, have brake light working correctly no service on dash, was able to turn traction control on and off it was perfect, I was so happy, I went through with the tech 2 and every module was 0 codes! I started putting everything back together and left it running while doing so and after 10 minutes BING traction control light came on and 2 seconds later the check engine light came up and the service stability reading on the dash, the brake lights still worked perfect. I fired up the tech 2 right then and I had 5 codes in the ecm, had 3 in the BCM, had 3 in the EBCM and 1 in the TCM. I cleared everything thinking it may been a clitch or something from monkeying around with things. They all cleared and started the car back and same issues they all came back rather quickly this time like in 5 seconds. I cleared one more time, I was going to right everything down from each module to make this post, and the codes came back as before the same exact codes in each module as before, I will list them bellow any help would be appreciated I have a connector or module dead somewhere IMO I would like and need some guidance any way thanks in advance. The brake lights are still working correctly as well.
Lane

ECM
P150C TCM engine speed request circuit
P0700 TCM request mil illumination
U0121 lost comm. with ABS
U0101 lost comm. with TCM
P2544 Transmission torque request circuit

BCM
U2108 lost comm. with ABS and traction control
U2106 lost comm. with TCM (I Think)?

EBCM
U0100 lost comm. with ECM/PCM
U0101 lost comm. with TCM
U0073 control module comm. bus off

TCM
U0073 lost comm. bus A off

Driver Door Module
U1017 lost comm. with ECM

ESCM No comm. ? suspension control may be in EBCM ??
EFCM No comm. ????

Thanks again
Lane

itomh

I know you said you checked the battery, but although it may test fine some say they get weird codes flashing due to battery being old. I know it sounds crazy, but battery issues have been known to cause traction control and ABS codes all the time. You should be able to find the topic here on the forum. If battery is older then 5 years you may try putting a new one in.

Faslane

Thanks the battery is 1 month old, i left the battery unhooked last night, I went out this morning and went to connect it back, but i decide to clean them a little. I cleaned the inside off them with sand paper till they were brass, i tighten them up very tight. Fixed.This has been the first time I have owned the car that there was not a light on the dash or had traction control.. Thanks for your response.

Dano523

Little trick, but when you are using the tech II, put at least a 10 amp charger on the battery.

When you put the car into run mode, motor not started, it drains the battery down fast with all the modules active, and this can cause some problems on the start up with the lower battery not allowing the BCM to see the modules on the land bus at start up check.

Hence look at the voltage gauge on the dash, and in just a few mins without a battery charger on the battery to keep up with the modules active in the start mod/engine off, your down to around 9 volts quickly and it can cause all kinds of code problems popping up.

Hell, just drain the battery down so the car will not start, use jumpers to get the car started again, and you will be littered with codes from the initial trying of starting the car with a dead/low battery in the first place.

If this does not solve the problem, then you need to start checking the GM land bus loop for a bad connection on the GM land bus wires, and in some cases since the loop goes through a module in the module for a bad cold solder joint as well.

Note, if you have a module in play, there is no jumper set around it. The loop goes through the module isntead. The loops that you see go around a module are only if the module is not installed in the car. Also to note, there are secondary loops off each module as well. Take the ECBM and you have a loop off it that picks up the Steering wheel sensor, as well the the SRS and yaw sensor, but all this information is feed back to the BCM via the primary loop on the ECBM. Hence with the codes your getting it's a problem on the primary loop, through the key modules.


Hence start here, and see if all the modules are showing up, can pull them out of sleep mode to begin with, and should narrow down where the problem is in either a connector/wire, or the module that needs to be pulled apart to resolve a cold solder joint problem on it internal loop instead.

Derek Adams

Subscribed because I have identical codes pretty much and same year car, with about double the miles.

Faslane

Thanks Dano.
You are probably corect, I had a battery charger on it but i had it on low setting i think 4 amps, and it did seem to get worse the more i messed with it.

I am a industrial electrician, I install many machines that have close to the same communication bus, we call it profibus, running the cable we start at the module farthest away and daisy chain our way back to the drive cabinet, both wires in a shielded cable. I dont really understand why GM connects the module the way they do? Takes 10 times as long to diagnose. Not a fan of using 2, 22 gauge wires for such a important task. But it is only 5 volts. Also while I am complaining for a 50k car new I would be embarrassed at the craftsmanship of the wiring and loom routing in this car. But I love my Corvettes, I will keep this updated. I will say I put more miles on the car today since ownership, and all is well. Thanks for your response
Lane.

Dano523

Just a FYI, but that big 20 amp fuse front and center on the BCM is the gm land bus/crank fuse.




So might help to pull it, clean it and the prongs, to make sure that the problem is not right there instead.

Faslane

Hello, issue came back, went and bought a new optima battery, cleaned the cable ends thoroughly, start it up and all was good, and it lasted about 20 miles, the active handling message check engine light, car will not shift, speedo acts a little funny, and the red BRAKE light may come on and go out. have not hooked the tech 2 but i am sure it is the same codes i posted earlier. When the car is good, its good. I have a short or loose connection in the GMLAN somewhere, what are the problem areas to check or how to narrow down where it is, i have done the bcm,brake switch, connection, grounds ect, i have check everything that i know of and the thing in the 1000 forum post i have read. Where is this bad connection?? please help!
Thanks
Lane

Dano523

When you have the problems, that is the time to use the Tech II to see what module(s) are not showing up on the GM land bus to start with, and then if its not one of the main modules, then what module sistered off the one of the main modules is not showing up next.

So here is the main gm land bus to start with,


With secondary modules off each one of the main modules as well (lot of the AH stuff comes off the ECBM module)



As for your initial list of codes, would dare to guess that the problem is in the VCIM or ESC modules, since they are up line of the ECBM that is losing commutation down line as well.

The VCIM is up behind the glove box on your year, while the ESC (real time dampening module) is behind the ECM in passangers front fender well area.

Faslane

Thanks very much, when i parked it last I unhooked the battery, therefor everything works and looks great for now. it may go 1 mile or 10 miles then goes to crap? you never know. Anyway my question is should i try to communicate with the modules know or wait till it goes to crap?

Dano523

Would just leave the tech II in the car, when dash lights up like a Christmas tree, then pull over, leave the car running and put the Tech II on it to find out what modules are not showing up. Hence enough jolting/modules warmed up enough for a Cold solder joint/bad connector connecting to start showing up then.

As for before hand, put the tech II on the car, go in DTC's and see what is listed currently. Hence until the fault count gets high enough to throw a actual trouble code in the DIC, the car will store DTC for if the problem only happened once or twice shortly isntead.

89Roadster

Have you checked all the fuses under the hood? I can't remember which one it was but a blown one will throw those TCM codes and give the active handling warning, also puts the car into limp mode, 1 gear only.

Faslane

I had some time this morning and take a look, and I have no communication with the modules pictured, I would assume that the one i need to worry about is the electronic suspension control, I took the inner fender out and the only thing there is the engine ECM, where else could it be? I do have the Bosch yawn sensor so I should have a ESC correct?

Dano523

lets back it up, and do you have these modules in the car in the first place.


If you don't have the memory buttons on the drivers door (1-r-2), your not going to have the memory modules in the seats.

EFCM is the NPP exhaust module, and if you don't have a NPP exhaust system, the car will not have that module

ESC is the F55 module and the dead give away would be a tour/sport button in the center of the console if you have that module in the car.

If its not a convertible, it not going to have a convertible top module.

same if you don't have a HUD installed in the dash.

If it not a 2005 manual, it not going to have a steering lock module as well.

So if the car is say a 1lt that did not come with most of the above options, then it normal for the Tech II to not communicate with the modules, since they are not installed in the car.

As for the yaw sensor to see if it has problems, look in the ECBM (brake) module data display for the level of the car position (rock the car and you will see the car angle change if the sensor is good). Same with the steering wheel sensor, since it will read out in this data too (turn the steering wheel).

If you need more help on what you are looking at on the tech II/trouble shooting the car, then click my name to the left, select PM from the drop down memo, and PM with a phone number to call you back.
Also, don't know what side of the world you on, but if your in the Denver area, can get together to make short work of the problems isntead.

89Roadster

If it's not a fuse take a look at the front connection of the transmission harness. A bad/corroded connection in that cable could cause those codes as the harness goes to the trans, the F55 position sensors, speed sensor and the rear hubs.

Faslane

All the data under the brake module looks great, one thing that did confuse me was the steering position sensor showed 3+degrees so I noticed it had a reset option, I then bumped the steering wheel till it was at 0 degrees and pushed reset and bam! the service stability and traction warning came up along with ABS light and the red BRAKE light also on. the weird thing was as soon as I exited that menu it all went away? I done this twice to see if it was a coincidence. As soon as you push reset bam lights, exit all goes to perfect. Also under the ABS pump menu it has LF-LR comm and comma, I would assume communicate and command, well they all said OFF, but all would switch too ON just for half a second every 1 minute or so? car in park? These two issues may be no big deal but things that seemed odd while digging a little deeper with the tech 2. It sat and idled flawlessly for 50 minutes, defiantly only pops up when driving. May be these things i noticed will help? in the mean time I will check the yaw sensor by rocking the car. I also have a membership at TIS 2 web and a MDI 2 but no subscriptions right now, if that would help in any way? Thanks for all your help. Lane.

Faslane

The fuse was fine, i will check the trans connector after dinner, I have checked it in the past but know a little more what to look for. Thanks for all your help! its something simple just takes time i quess. lol.
Thanks again
Lane

Dano523

Normal, and when you do the auto power bleed on the ABS system with the tool to cycle the pump and valves, you get all kinds of lights and service warnings until the process is completed as well.

At this point, looks like it time to take the car for a drive to jolt things around a bit, and when you do get the service bells and whistles, then pull over to figure out what module(S) lost contact on the GM land bus while the car is still running, since the problem is screaming either a bad connector or bad solder joint on one of the boards.

And yes, electrical gremlins on the Vet blow big time; hence resolving them is the easy part in the end, but finding them to begin with, the worst part isntead.

Faslane

Thanks, I have my little girl this weekend, plus dont care to drive in rain, as soon as i get a chance to drive it i will post up what i find
Thanks again
Lane

Faslane

been driving it to the store or parts house, nothing is showing up? It will come lol