DTC 41 - I need help!
06-12-2008, 11:29 PM
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DTC 41 - I need help!
I am fed-up with my car and hope someone can help. Here is my story:
Backround:
1. 1995 LT1, 6-speed (polo green w/ saddle leather), 75,000 miles. Overall, good shape.
2. Owned car for 6+ years; great runner until 4 months ago. Love the car and want to drive it again.
It's been too long. I am generally a novice, but I have the FSM's and lots of tools & testers. I am a hands-on type of person.
So here we go . . . . . . .
3. Darn! . . . spun several crank bearings in the original engine. That's water under the bridge. Maybe I will rebuild that motor some day.
4. I installed new long block 383 from well known builder; New MSD opti, water pump, wires, plugs, coil, etc. I am/was proud I accomplished that.
5. Startup: Broke-in the engine in according to builder instuctions. After 1 hour, it started hestitating/cutting-off at 2,000 rpm. Then turns-over, but no start. Follow FSM. Bad ICM . . . I forgot to use the heat grease.
I buy a new ICM, but only cranks, no start. I followed the FSM again, found no output from PCM to ICM on ICM plug C. Bought a remanufactured PCM from AcDelco and installed it. Car starts right up, but only runs 2 seconds. (For the 2 seconds it runs, it sounds great
)
6. Current situation:
a. Starts, but only runs about 2 seconds.
b. Module 1 DTC C41 - Loss of PCM serial data.
c. Module 1 DTC C54 - FEDS - Fuel Enable Failure
d. Module 9 DTC H72 - Serial Data Line malfunction.
e. DataMaster will reports loss of communication when I try to link via the DLC.
f. Car has Electroncs Climate control (C68) - Green 'on/off' switch is blinking.
g. I can not read the PCM via RTuner.
h. The Service ASR and ASR Off lights come on at a regular intervals, both together, and then go off, together. And repeat again & again with ingition in run. Car not running.
i. Using the on-board diagnostics, I have gotten to 1.3, then looked at value for the "Pass-Key fuel" input. The value is 1 = Enabled. I'm note sure if this is good or bad.
j. I have physically checked ground point G107 several times. No apparent problems. I have consolidated ground point G106 onto G107 because the new block was painted and I thought this might not be enabling a good ground. No change. Might I have caused a problem by doing this?
k. I get 'err' in the diagnostic mode, most often for the A. module, but also on modules 4 and 9 intermittenly.
l. My battery is fully charged.
m. Diagnostic module 4 reports a lot of historical codes: H46, H59, H71, H73, H83, H90. I think these are all a result of the serial data communications problem.
Anyone have any ideas on how to fix this? Or what to check? Sorry if I used wrong terms in this post, I am still a newbee at this
. And thanks for reading through this long post.
Ron
Backround:
1. 1995 LT1, 6-speed (polo green w/ saddle leather), 75,000 miles. Overall, good shape.
2. Owned car for 6+ years; great runner until 4 months ago. Love the car and want to drive it again.
It's been too long. I am generally a novice, but I have the FSM's and lots of tools & testers. I am a hands-on type of person.
So here we go . . . . . . .
3. Darn! . . . spun several crank bearings in the original engine. That's water under the bridge. Maybe I will rebuild that motor some day.
4. I installed new long block 383 from well known builder; New MSD opti, water pump, wires, plugs, coil, etc. I am/was proud I accomplished that.
5. Startup: Broke-in the engine in according to builder instuctions. After 1 hour, it started hestitating/cutting-off at 2,000 rpm. Then turns-over, but no start. Follow FSM. Bad ICM . . . I forgot to use the heat grease.
I buy a new ICM, but only cranks, no start. I followed the FSM again, found no output from PCM to ICM on ICM plug C. Bought a remanufactured PCM from AcDelco and installed it. Car starts right up, but only runs 2 seconds. (For the 2 seconds it runs, it sounds great
)6. Current situation:
a. Starts, but only runs about 2 seconds.
b. Module 1 DTC C41 - Loss of PCM serial data.
c. Module 1 DTC C54 - FEDS - Fuel Enable Failure
d. Module 9 DTC H72 - Serial Data Line malfunction.
e. DataMaster will reports loss of communication when I try to link via the DLC.
f. Car has Electroncs Climate control (C68) - Green 'on/off' switch is blinking.
g. I can not read the PCM via RTuner.
h. The Service ASR and ASR Off lights come on at a regular intervals, both together, and then go off, together. And repeat again & again with ingition in run. Car not running.
i. Using the on-board diagnostics, I have gotten to 1.3, then looked at value for the "Pass-Key fuel" input. The value is 1 = Enabled. I'm note sure if this is good or bad.
j. I have physically checked ground point G107 several times. No apparent problems. I have consolidated ground point G106 onto G107 because the new block was painted and I thought this might not be enabling a good ground. No change. Might I have caused a problem by doing this?
k. I get 'err' in the diagnostic mode, most often for the A. module, but also on modules 4 and 9 intermittenly.
l. My battery is fully charged.
m. Diagnostic module 4 reports a lot of historical codes: H46, H59, H71, H73, H83, H90. I think these are all a result of the serial data communications problem.
Anyone have any ideas on how to fix this? Or what to check? Sorry if I used wrong terms in this post, I am still a newbee at this
. And thanks for reading through this long post.Ron
06-13-2008, 06:36 AM
#2
I don't have a 96 FSM to follow your diagnostic procedure but it sounds like most of your issues started after the PCM replacement. Have you contacted the seller to see if they will exchange it? Remans are not always perfect unfortunately. Good luck, sorry it has turned into such a nightmare.
06-13-2008, 09:23 PM
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Le Mans Master
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St. Jude Donor '05-'06
I don't have a 96 FSM to follow your diagnostic procedure but it sounds like most of your issues started after the PCM replacement. Have you contacted the seller to see if they will exchange it? Remans are not always perfect unfortunately. Good luck, sorry it has turned into such a nightmare.
Return it and get another.Mabey the PCM plug is not on right?You have provided lots of info and there is a serial link between the PCM and CCM and that sounds like what is fubared. Start with the new PCM.Clear all the codes and try again.Get rid of the history codes and see if they come back. If a new PCM does not solve it time to check the CCM.
Last edited by Redeasysport; 06-13-2008 at 09:29 PM.
06-13-2008, 10:38 PM
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Here is what I have gone tonight so far:
1. Took the Climate controller, ASR and DERM off the Serial Data Link leaving just the CCM and PCM. No change. Still starts right up, sounds good and dies two seconds later.
2. I can not clear DTC codes in modules 1 and 4, using 1.7 & 4.7 of the on-board diagnostics.
3. I attached a noid light to one injector harness. The light appears to confirm that the injector is being triggered for the first 2 seconds and then light stops, engine stops.
4. I double checked each connection to the PCM.
I am beginning to suspect that the remanufactured PCM I purchased is bad also. What do you think?
Thanks to all who replied!
Ron
1. Took the Climate controller, ASR and DERM off the Serial Data Link leaving just the CCM and PCM. No change. Still starts right up, sounds good and dies two seconds later.
2. I can not clear DTC codes in modules 1 and 4, using 1.7 & 4.7 of the on-board diagnostics.
3. I attached a noid light to one injector harness. The light appears to confirm that the injector is being triggered for the first 2 seconds and then light stops, engine stops.
4. I double checked each connection to the PCM.
I am beginning to suspect that the remanufactured PCM I purchased is bad also. What do you think?
Thanks to all who replied!
Ron
06-13-2008, 10:42 PM
#7
Le Mans Master
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St. Jude Donor '05-'06
It happens. I don't know what testing they do when they reman them but I bet they do not put them in a car. Sounds like you have done a thorough check out and are now seeing the trees through the forest.
