Car model and year:
2005 Chevrolet Corvette M6 base
Symptom:
Brake lights are not working. Including the 3rd brake light.
GM scanner:
I do have an Autel 519.
GM Tech II scanner (is a must tool)
What I tried to do:
Replaced the brake light switch. Swapped back in the original. Still no brake lights.
What should do next? (From experienced user)
When changing the BPS, did you do a relearn with a Tech II to calibrate it with the BCM.
When you have the tech II on the car to do the BPS relearn, did you go into BCM data after to see if the pedal was signaling the BCM to turn on the brake lights?
Hence problem could be BPS not calibrated correctly to start with at the BCM, or could be the wiring/rear bumper void connector, or just rear grounding the problem instead.
And if you don’t own a Tech II ( at least clone) to work on the car, it’s your first mistake, since even basic items like brake pedal sensor replacement have to be calibrated to the BCM via the tool. So on that note, if you list your location, someone local may have a Tech II to put on the car, until you get your own.
For Autel 519
The brake position sensor is a restate type device, not a on/off switch. So when it replaced in the car and since the each sensor will have a slightly different reading, the BCM has to learn it value when the pedal is not pushed, then when the pedal is pushed.
Double check your Autel 519, but not sure is has a BPS relearn for the GM cars on it, which is required when the brake pedal sensor is replaced.
Once the BPS vavlues have been learned to the BCM, then you can go into BCM data to make sure that the BCM is seeing the changing rates, and activating the brake lights. From here, then we are done to just the fuse and wiring from the BCM to the lights (then ground).
So again, could be the old BPS is worn, and its current resitance values are not the ones first leaned in, the replace values where never learned in, and why the BCM is not seeing the correct values to turn on the brake lights to begin with.
Finally, Solved!
I took the car to my friend’s shop. He fixed it in 5 minutes with a BPS relearn. I’m not sure why this was required. I did change out the switch but I put the original back in. Or the previous owner could have changed it and not known a relearn was required. He actually knocked quite a bit of money off the car because of this issue. Either way I have brake lights!
Good to know:
I have/used just about every Tech II / MDI device known, and it’s the VX GM Nano’s that I use the most (have one in both usb and wifi versions).
Hence it works at both a Tech II using cracked Tech2win software for the C6 and back cars for free that comes with it, and since it is a MDI clone to being with, works for C7 and newer cars running GSD2/TDS as well.
Hence the problem with the hand held tech II clones, is they only work on C6 or later cars, and not the newer cars that need MDI running GDS2 instead.
Regarding using TIS2000 with a hand held tech II clone, the unit only comes with a rs-232 connector cable, so you end up having to pick up a usb cable to connect it to a machine to run tis2000 instead.
So quick break down of GM software.
Tech2win is the same software that the hand held tech II’s runs internally, but runs it on a laptop instead. It’s used for diagnostics, and a few relearn type features.
Tis2000 is used for SPS firmware flashing of the C6 cars back. Note, there is the standard version that only goes up to 2009 cars, then there is the abroad version for spotty internet areas that will go up to 2013, since TDS may not work correctly if the area internet is not fast enough (think abroad where a service area may only have phone dial up).
GDS2 is the diagnostic and some relearn items for the 2014 and up cars.
TDS is the on-line SPS programming that replaced Tis2000 for the new cars from 2009 up for most firmware and special programming, even on the older cars.
As for the VX GM nano, runs all the above software, and in most cases (short of TDS that you would need to pay for a subscription), does so for free. Hence this is the reason that it’s favored, since it covers me on pretty much any GM car running no service fee software..
Credits to @Dano523 (CF Senior Member)
For the reliable clone GM TECH2, MDI and VXDIAG NANO GM, you are advised this one:
GM TECH2
VXDIAG NANO GM (USB)
VXDIAG NANO GM (WIFI)