Need help from my forum friends
02-03-2007, 05:06 AM
#1
Drifting
Thread Starter
Need help from my forum friends
To start with, my car was working fine prior to this problem. I made a minor edit to my custom program and did a calibrated write to my PCM using HPTuner software version 2.1.16.0. After the download, it said download 100% but did not exit as it normally did in previous downloads. I disconnected from the OBDII connector and turned the key back on ( did not try to start it) and got the following indications:
CHECK ENGINE LIGHT
TRACTION LIGHT
ABS LIGHT
SECURITY LIGHT
CHECK GAGES LIGHT
DIC Displayed:
CORVETTE BY CHEVROLET
REDUCED ENGINE POWER
SERVICE VEHICLE SOON
LOW FUEL
SERVICE ABS
DIAGNOSTIC READOUT
10-PCM NO COMM.
28-TCS C1255 H
C1276 H C
U1255 H C
40-BCM U1255 H C
60-IPC NO CODES
80-RADIO NO CODES
99-HVAC NO CODES
A0-LDCM NO CODES
A1-RDCM NO CODES
A6-SCM NO CODES
B0-RFA U1000 H C
Now my HPTuner could not find my VCM when I tried to re-program it to see if it would work this time. I assume that the PCM has lost it's ability to communicate over the serial link since it says PCM NO COMM and I've probably fried my PCM. Any PCM experts out there that can give me guidance? Has anyone else experienced something like this? Thanks for any help.
John
CHECK ENGINE LIGHT
TRACTION LIGHT
ABS LIGHT
SECURITY LIGHT
CHECK GAGES LIGHT
DIC Displayed:
CORVETTE BY CHEVROLET
REDUCED ENGINE POWER
SERVICE VEHICLE SOON
LOW FUEL
SERVICE ABS
DIAGNOSTIC READOUT
10-PCM NO COMM.
28-TCS C1255 H
C1276 H C
U1255 H C
40-BCM U1255 H C
60-IPC NO CODES
80-RADIO NO CODES
99-HVAC NO CODES
A0-LDCM NO CODES
A1-RDCM NO CODES
A6-SCM NO CODES
B0-RFA U1000 H C
Now my HPTuner could not find my VCM when I tried to re-program it to see if it would work this time. I assume that the PCM has lost it's ability to communicate over the serial link since it says PCM NO COMM and I've probably fried my PCM. Any PCM experts out there that can give me guidance? Has anyone else experienced something like this? Thanks for any help.
John
02-03-2007, 06:13 AM
#2
Melting Slicks
Member Since: Sep 2006
Location: Rockford Illinois
Posts: 2,041
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To start with, my car was working fine prior to this problem. I made a minor edit to my custom program and did a calibrated write to my PCM using HPTuner software version 2.1.16.0. After the download, it said download 100% but did not exit as it normally did in previous downloads. I disconnected from the OBDII connector and turned the key back on ( did not try to start it) and got the following indications:
CHECK ENGINE LIGHT
TRACTION LIGHT
ABS LIGHT
SECURITY LIGHT
CHECK GAGES LIGHT
DIC Displayed:
CORVETTE BY CHEVROLET
REDUCED ENGINE POWER
SERVICE VEHICLE SOON
LOW FUEL
SERVICE ABS
DIAGNOSTIC READOUT
10-PCM NO COMM.
28-TCS C1255 H
C1276 H C
U1255 H C
40-BCM U1255 H C
60-IPC NO CODES
80-RADIO NO CODES
99-HVAC NO CODES
A0-LDCM NO CODES
A1-RDCM NO CODES
A6-SCM NO CODES
B0-RFA U1000 H C
Now my HPTuner could not find my VCM when I tried to re-program it to see if it would work this time. I assume that the PCM has lost it's ability to communicate over the serial link since it says PCM NO COMM and I've probably fried my PCM. Any PCM experts out there that can give me guidance? Has anyone else experienced something like this? Thanks for any help.
John
CHECK ENGINE LIGHT
TRACTION LIGHT
ABS LIGHT
SECURITY LIGHT
CHECK GAGES LIGHT
DIC Displayed:
CORVETTE BY CHEVROLET
REDUCED ENGINE POWER
SERVICE VEHICLE SOON
LOW FUEL
SERVICE ABS
DIAGNOSTIC READOUT
10-PCM NO COMM.
28-TCS C1255 H
C1276 H C
U1255 H C
40-BCM U1255 H C
60-IPC NO CODES
80-RADIO NO CODES
99-HVAC NO CODES
A0-LDCM NO CODES
A1-RDCM NO CODES
A6-SCM NO CODES
B0-RFA U1000 H C
Now my HPTuner could not find my VCM when I tried to re-program it to see if it would work this time. I assume that the PCM has lost it's ability to communicate over the serial link since it says PCM NO COMM and I've probably fried my PCM. Any PCM experts out there that can give me guidance? Has anyone else experienced something like this? Thanks for any help.
John
I would try and dis connect the battery for a few minutes and see if anything resets.
02-03-2007, 08:07 AM
#3
Hows your battery ???
I think it says somewhere in the HP tuners info that you should have a minimum of 11.7 volts (or something like that) before trying a write.
My car sits for a while sometimes and I remember wierd things happening when I tried to acces the PCM with a weak battery.
Clear the codes and try to start the car and see what happens.
I think it says somewhere in the HP tuners info that you should have a minimum of 11.7 volts (or something like that) before trying a write.
My car sits for a while sometimes and I remember wierd things happening when I tried to acces the PCM with a weak battery.
Clear the codes and try to start the car and see what happens.
02-03-2007, 09:25 AM
#4
Drifting
John,
Make sure your courtesy fuse isn't blown.
I've had this happen, but was able to recover by doing a write entire of the current tune.
I assume you have tried shutting everything down.
Make sure you wait 15 sceconds or so before trying to connect.
Sorry I can't be of more help.
It's a sick feeling when this happens on the side of the road...
Make sure your courtesy fuse isn't blown.
I've had this happen, but was able to recover by doing a write entire of the current tune.
I assume you have tried shutting everything down.
Make sure you wait 15 sceconds or so before trying to connect.
Sorry I can't be of more help.
It's a sick feeling when this happens on the side of the road...
02-03-2007, 10:22 AM
#5
Le Mans Master
make sure the battery is fully charged. I would call hypertech the # is in the owners manual. they would be the best source of free information as I'm sure this aint the first time this happened on a C5
good luck
good luck
02-03-2007, 10:46 AM
#6
Safety Car
The first time this happened to me I was using LS1Edit, and I was able to get it back. Talk about sweaty palms!
---
I would check the courtesy fuse as FRCTony suggested, if it's not that then you may have a PCM with a 'crashed OS'. I've had this happen a few times with EFILive. I have a knife switch on my battery, so I just disconnect it for about 5 mins. and it's always come back. They have a term for it in the EFILive manual, "Zombie". This happens when the write didn't work as expected and maybe there was noise on the comms line or something, sounds like your case.
---
As I understand it, there are several areas in the PCM. One of them is the Program Flash, and another is the Operating System. If you didn't do a full reflash, your operating system is most likely intact. It's possible you 'crashed' your operating system and it just needs a reboot.
I hope that's the case.
---
I would check the courtesy fuse as FRCTony suggested, if it's not that then you may have a PCM with a 'crashed OS'. I've had this happen a few times with EFILive. I have a knife switch on my battery, so I just disconnect it for about 5 mins. and it's always come back. They have a term for it in the EFILive manual, "Zombie". This happens when the write didn't work as expected and maybe there was noise on the comms line or something, sounds like your case.
---
As I understand it, there are several areas in the PCM. One of them is the Program Flash, and another is the Operating System. If you didn't do a full reflash, your operating system is most likely intact. It's possible you 'crashed' your operating system and it just needs a reboot.
I hope that's the case.
Last edited by ArKay99; 02-03-2007 at 10:51 AM.
02-03-2007, 11:38 AM
#8
Drifting
Thread Starter
Thanks guys, I forgot to mention my battery was good and I tried to disconnect/reconnect the battery to re-boot the PCM. Will try it one more time and then it's PCM replacement time unless someone comes up with a suggestion we haven't thought of already. Not sure what the courtesy fuse has to do with it but I'll check it out anyway. I was just wondering if anyone has had the PCM NO COMM failure before and what they did to correct it.
There's one explaination I can think of besides the obvious low battery problem during the write. It's possible that my HPTuner pod could be at fault. Doing a calibrated write should have only written to an isolated portion of the flash for tuning. But if the pod had failed, maybe writes were going other places in the flash as well which would explain everything. Thinking I'll send my serial cable/pod in to have it checked just to be safe.
Thanks.
John
There's one explaination I can think of besides the obvious low battery problem during the write. It's possible that my HPTuner pod could be at fault. Doing a calibrated write should have only written to an isolated portion of the flash for tuning. But if the pod had failed, maybe writes were going other places in the flash as well which would explain everything. Thinking I'll send my serial cable/pod in to have it checked just to be safe.
Thanks.
John