ECM/CCM Serial Link Problem
Thread Starter
Heel & Toe
Joined: Jun 2005
Posts: 18
Likes: 0
ECM/CCM Serial Link Problem
Greetings: My 93 displays "sys" in odometer area with security flashing. I get C41, H41, H54 and H72 when I run CCM test. Also get "err" on test #4. ECM diagnostic gives 12...so its OK I guess. It fires then immediately dies. The flashing "sys" has gone from intermittent to immediately coming on when I turn the key. (There is pressure on fuel rail ruling out fuel pump, etc.)
I have a service manual and based on what I read I am suspecting serial link down. Furthermore, I suspect CCM not sending FEDS fuel enable to injectors so ECM shuts them down immediately after a successful crank. (when ECM and CCM find out they can't communicate). In early stages of problem, I got "Check ASR" on dash but I could start the car. Now its dead. Am trying to avoid large tow bill to Chevy dealer. Someone mentioned ECM loading down serial link to CCM and its probably ECM vice CCM.
If an ECM is needed, where's the best place to purchase one?
Any advice would be greatly appreciated.
I have a service manual and based on what I read I am suspecting serial link down. Furthermore, I suspect CCM not sending FEDS fuel enable to injectors so ECM shuts them down immediately after a successful crank. (when ECM and CCM find out they can't communicate). In early stages of problem, I got "Check ASR" on dash but I could start the car. Now its dead. Am trying to avoid large tow bill to Chevy dealer. Someone mentioned ECM loading down serial link to CCM and its probably ECM vice CCM.
If an ECM is needed, where's the best place to purchase one?
Any advice would be greatly appreciated.
Instructor
Joined: May 2005
Posts: 162
Likes: 0
From: Lady Lake FL
I just sent you a PM about this. I had the same prob and replacing the ECM with a working one fixed my problems. I looked around for a replacement ECM before finding one from someone on the forum here that lives 20 minutes away for alot less than the $318 I paid at Advance Auto (that worked for a day). 
Also, ZIP has them for $95.
KC
Also, ZIP has them for $95.KC
Race Director
Joined: Apr 2004
Posts: 17,066
Likes: 3
From: Milpitas ca
Originally Posted by rubydog
If an ECM is needed, where's the best place to purchase one?
Any advice would be greatly appreciated.
Any advice would be greatly appreciated.
