ECM been changed? Odometer reading ---
 

Is there a way to tell if the ECM in my car isn't the one that came with it from the factory?

Im chasing an issue with my odometer and tripometer not reading anything (---). I was thinking it was the bcm but its been flashed and still no odometer reading.

Any ideas or what else to check for?

There is no way to know if the ECM was changed, you can flash a used ECU using SPS to the exact VIN and calibration and it will be exactly as the factory ECM.
The odometer reading doesn't come from the ECU, it's stored directly in the cluster. I have changed ECUs many times and the odometer remains the same. If you change the cluster to another vehicle the odometer follows the cluster so I think you have a bad cluster. I'm not 100% sure but I remember that if you unplug the ECU from the harness the odometer still reads the same.
Which vehicle is this?

Thank you!

It's on a 2010 Camaro SS. Car started out as an auto then switched to a full manual valve body hybrid 4L80. After the switch the odometer wasn't working along with many other things. Actually it does work it just reads ---
Flashed the bcm and everything started working fine except the Odo, trip-meter, sunroof and "some" but not all the interior lights. Not sure where else to look to try to figure out how to get the odometer, sunroof and interior lights to work.

If it was an auto then you need to flash the ECU and Cluster to a full manual tune. The auto uses a TCM that sends the speed signal to the ECU and cluster. Now with the 4L80E there is no TCM so the Vss signal must be sent directly to the ECU, then the ECU will transmit the Speed signal to the CAN Bus for all the modules that use is (Cluster, ABS). For this to work you need a manual flash in the ECU to enable the Vss input and the cluster may also need a manual calibration. You also need to wire the Vss sensor to the ECU.
Interior lights and sunroof are controlled by the BCM, you need to use a calibration that matches the equipment installed in the car, they are very special about that. The BCM hardware must also be the correct one since they won't work correctly if the hardware is different.

Exactly the info I've been looking for. Been trying for awhile now to wrap my head around how its all done, and you've explained it perfectly! I appreciate it.

Most of it makes perfect sense and I've got the Vss signal going to the ECU and then transmitting out the correct signal to cluster and abs. What I don't understand is the manual tune. I assumed that in order to get a manual tune into the ECU, I would need a vin number from a manual car. My ECU tune matches my auto vin, so this part is what doesn't make sense to me, unless I'm missing something when looking at the tune using HPT.

The manual tune needs to be flashed using GM's SPS service and a J2534 tool. HPT is not the correct tool to do it, it may work if you write entire a manual file of the same year but it may not work or brick the ECU.
After the ECU is flashed with the correct manual calibration you can use HPT to change the VIN to match the car leaving the calibration intact.
The manual calibration will enable the Vss input in the ECU to work correctly. It may somehow work with the auto tune but will never work correctly.

Thank you

Would a dealership be one of my only option or the only option there is?

No we can flash it for you if you mailed it in.

Are you able to flash the cluster also if its needed or do you think flashing the ECU would take care of the cluster as well?

I dont have a way to flash the cluster outside of the car. Your cluster, bcm, and ecm should all have the vin in them. A bcm can only be flashed once in a 5th gen from what we have seen but the cluster can be reflashed.

Would either of you be willing to look at my tune to see whats going on? See if anything jumps out at you to help me get this problem corrected?

If it wasnt flashed with SPS looking at it with tuning software wont help much IMO. All the changes with SPS wont show up in HPT since HPT doesnt flash all the segments.

Can I ship my cluster to you to have you flash it for me and send it back?

Sorry we dont have a way to flash a cluster outside of the vehicle.

i'm having the exact same problem with a 13 camaro, we swapped from auto to manual. I have access to gm sps programing we flashed a different vin in the ecm and bcm and right after that the mileage is inop shows --- lines. everything else in the car works fine and the mileage was working before. the mileage is stored in the bcm I can see the mileage in the bcm under live data but it doesn't show on the cluster. I talked with one of the guys at work and he said, I may need to unplug the clutster , program the bcm again, then cluster should work. he said something about the cluster having to re sync to the bcm after it was flashed. I haven't had time to reflash the car again. I will try to you guys posted if I get it back working.

After months of research on this and many leads leading to nowhere I *think* I have an understanding on whats going on. We are getting the dash lines because our clusters have now locked us out. This happens when a Vin from another camaro is flashed into the bcm to *try* and make things work. Been told I need a new bcm and cluster both flashed to my vehicles vin. In a nut shell........I still have no idea whats going on lol. Right now your my only hope I guess, because the guy who gave me the info above, has stopped emailing me back. If you figure this out or get pointed in another direction that could help us both, please don't forget about your lonely brother sitting here like a lost puppy trying to get with this. It would sure be appreciated.

last night I tried flashing the new vin in the cluster and it completely locked up. no lights, gauges, no communication. but I did find out that the bcm is still logging mileage. it maybe true that the bcm and cluster will have to be replaced at the same time. I think my buddy is going to buy a used cluster and just deal with the mileage thing. I did find a document stating the problem is a vin mis-match with bcm, it also stats that ipc can be reprogramed to correct issue but at the end of document ipc may still need to be replaced.

Ok at least were making progress on tracking down the correct issue. Thank you for the update. Nothing new on mine so far.

From what we have seen you can only flash the bcm once....when we ran into this we put new bcm in and flashed it and everything was good.

I've heard this also, but haven't seen it confirmed just yet.