Code U1301 data link 2 high - Chevrolet Forum - Chevy Enthusiasts Forums

Code U1301 data link 2 high

Old  September 25th, 2012, 6:19 PM
Code U1301 data link 2 high

This is on a 2004 chevy malibu 3.5 engine using a tech II to read the codes, using the data 1 all systems show ok. I am going to check all grounds and connections, let me know if you have any ideas or experience with this code. The engine will die all of a sudden and then start back up while driving and once after an idle time of 8 mins.

Old  September 25th, 2012, 8:37 PM
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check the class 2 serial data line for a short to voltage.
with your voltmeter set to min/max. koeo, what is the max voltage you get from pin2 at the dlc connector. red lead to pin 2, black lead to ground.

Old  September 26th, 2012, 12:21 PM
Thank you the voltage readings are good. I cleared all codes did a re-learn on the crank postion sensor that I installed. I drove the car about 7 miles and it died again re-started ok then after about 100 ft it died again. Re-started ok came home to my garage hooked up my tech II got codes of 335 crank position sensor and also 455 evap large leak. But the U1301 is gone hope that cleaning the connections there fixed that problem. I see others have had the same problem but they all seem to be on the 4 cyl engines not a 3.5 like this one. Since I have retired I no longer have a pass word for the napa line to find problems such as this so hope some one who has had this problem with a 3.5 2004 malibu might share a fix.

Last edited by icemanthe1; September 26th, 2012 at 4:02 PM.
Old  September 28th, 2012, 7:52 AM
I am still looking for advice on this condition, I have test drove the car 8 times since clearing all codes no code has re appeared. So now when it dies while driving no codes are present. Not sure why those codes came up before but I have cleaned all grounds and made sure they are tight, cleaned and inspected all connections using a very bright light and a magnifing glass.Checked all wires at the connections to all sensors and at the PCM for breaks or cracks. But it still dies while driving and in some cases it has died while in my garage at idle. I will be happy to listen and try any thoughts to all advice, I just don't want to begin throwing parts at it at this time.

Old  September 29th, 2012, 9:37 AM
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have the techII scan tool triggered to record a snapshot when the fault occurs. Plot the data and look for signal dropouts. That will give you a starting point

Old  September 30th, 2012, 7:02 AM
Thank you yes I will try that again today yesterday I had it recording when it only did a small hic-cup but did not die. the car is 8 years old but only has 115,00 its my daughters car. I have been told to replace the pcm but I don't feel the pcm is the problem. Something is causing the engine to skip and that is causing the CKP to not read its rotation properly. I will follow your advice today and hope I get some info from the snapshot.

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