Dead ECM? Anything else possible???
Thread Starter
Race Director
Joined: May 2005
Posts: 11,992
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From: Middletown, DE
Dead ECM? Anything else possible???
Please help -- 93 LT1 6-speed. Pulled out of the development tonight, accellerated and the car began to buck. Immediately, the "Service ASR" and "Service Engine Soon" lights came on. The "sys" and "security" lights started to blink. Was able to proceed, but car hit brick wall at 3K RPM. Idled bit rough and high -- 1500 RPM. Seems like A/C stopped blowing cold as well.
Came home and pulled codes -- got the following: CCM codes (1): C41 and H41 ("ECM Data Communications Lost"); ECM Codes (4): Err; and EBCS Code (9): 72 ("Serial Data Link Error").
Two more pieces of info -- I am running a PCMforless chip that has worked great since I installed it 30 months ago. The prior owner installed a new ECM 4 years ago at 81K miles; car now has 111K miles.
I am guessing none of this is good -- ECM? CCM? Something unexpected and wierd? If ECM, I understand these are rare -- any ideas where to get one?? I am going to start checking out my FSM but I find it a bit hard to navigate -- would greatly appreciate help from those with experience.
Thanks much; this is my DD and I need to take a trip next week
Came home and pulled codes -- got the following: CCM codes (1): C41 and H41 ("ECM Data Communications Lost"); ECM Codes (4): Err; and EBCS Code (9): 72 ("Serial Data Link Error").
Two more pieces of info -- I am running a PCMforless chip that has worked great since I installed it 30 months ago. The prior owner installed a new ECM 4 years ago at 81K miles; car now has 111K miles.
I am guessing none of this is good -- ECM? CCM? Something unexpected and wierd? If ECM, I understand these are rare -- any ideas where to get one?? I am going to start checking out my FSM but I find it a bit hard to navigate -- would greatly appreciate help from those with experience.
Thanks much; this is my DD and I need to take a trip next week
Thread Starter
Race Director
Joined: May 2005
Posts: 11,992
Likes: 1,331
From: Middletown, DE
Thanks for the comment. I checked the cables (tight and clean) and the battery appears to be pumping out plenty of juice (cranks fast and starts right up). Have not checked alternator -- no equipment or training. But, I finally read thru my FSM and found an interesting clue. On page 5E2-108 (which refers to EBTCM codes), it says "CCM DTC 41 will likely be set along with this DTC if the problem is a short to ground or B+ on the serial data circuit." So maybe that's my problem -- is the alternator on that circuit?
Anybody ever have this specific problem on their LT1? is it easy for a total novice to trace?
Thanks again -- assuming I'll eventually need to take this to a mechanic at least I'll be a more informed customer..
Anybody ever have this specific problem on their LT1? is it easy for a total novice to trace?
Thanks again -- assuming I'll eventually need to take this to a mechanic at least I'll be a more informed customer..
Thread Starter
Race Director
Joined: May 2005
Posts: 11,992
Likes: 1,331
From: Middletown, DE
Yanked the piggyback chip and went for a short ride -- problem gone. Cleared codes and went for a cruise. No problems, no codes.
I'll be sending Alvin at PCMforless a note about this. I am really surprised the chip could cause such a problem; and I really liked the boost it gave when I first installed it. Maybe just a coincidence and the ECM is waiting to croak totally; maybe not.
I'll keep everyone posted.
Thanks,
Fred
I'll be sending Alvin at PCMforless a note about this. I am really surprised the chip could cause such a problem; and I really liked the boost it gave when I first installed it. Maybe just a coincidence and the ECM is waiting to croak totally; maybe not.
I'll keep everyone posted.
Thanks,
Fred
