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Pete, Buick Technician
Category: Buick
Satisfied Customers: 27814
Experience:  17 years Buick Technician experience and training.
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Buick LeSabre Custom 2000 buick lesabre fault codes u1301,u1016,u1040,u1096,u1064,c1235,c

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2000 buick lesabre fault codes u1301,u1016,u1040,u1096,u1064,c1235,c1244,p1602,p1626
dash display goes to all symbols, security light on gauges inop
scan tool loses communication when car is started, codes will all clear when not running and all return as soon as started
Where do I Begin?.... Inspected harness already...
Hello,I will be glad to try and assist you with this,Welcome to Just Answer.


I just need a little more info to assist better.

Can you tell me what harnesses were inspected?

Was anything done to the vehicle before this happened?

Let me know so we can continue,Thanks Pete!
Customer: replied 5 years ago.
My technician tells me he has inspected harness at and near all termination points and checked all grounds. We just got this one in today so we are unsure of any previous work.

Code P1301 will set when the scan tool cannot communicate with the vehicle,the other U codes set are for the PCM,EBCM,IPC and DIM control modules not communicating on the data list.

One very common problem that can cause these codes is power or ground loss to these control units.Since they all have their own power and ground supply on seperate circuits most likley this isnt the seperate circuit at fault or a seperate ground at fault.This may be a loose or corroded battery cable at the battery or alternator or even starter or where the ground runs to from the battery.These all need checked.

If these are all o.k. it may be possible the electronic ignition switch is failing and not providing any power or enough power to these components at key on or intermittently>i have seen this switch fail before and cause this condition.

I believe the other P and C codes will also clear up once the U code fault has been corrected as usually these control units will cause these other codes to set when a loss of communication code is set like this here.

If one of these components (PCM,EBCM,IPC,DIM) are shorted internally it can short out the data line and cause these codes to set.You would have to disconnect each of these one at a time and then see if the other control units communicate after words,if they do then the last component unplugged is the source of the problem and needs replaced.

Let me know if you need anything else,click accept if you feel satisfied with your answer as this is how I get credited for my time,Thanks Pete!
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