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What symptoms encouraged you to seek out codes? If the answer is none then disconnect the scan tool and forget about it. It's not uncommon to have communication codes stored and does not necessarily mean that there is a problem.
I would agree.
If you have no trouble DTC to key on, all the U codes are past history.
Something happened that caused those Modules to lose >communications< on the LIN (local interconnect Network.).
Only way to get them cleared out is to put a request in for Diagnostics on each one that will come back all tests passed.
Playing with power, turning the ignition on and off etc can cause U codes if done while the system is booting up.
Its an interruption in the middle of an action.
Good luck.
I would agree.
If you have no trouble DTC to key on, all the U codes are past history.
Something happened that caused those Modules to lose >communications< on the LIN (local interconnect Network.).
Only way to get them cleared out is to put a request in for Diagnostics on each one that will come back all tests passed.
Playing with power, turning the ignition on and off etc can cause U codes if done while the system is booting up.
Its an interruption in the middle of an action.
Good luck.
Just a comment I think may be in relation to what you have given the OP here....
Whenever I startup my truck, I will key on and then wait about 10 seconds before turning over the engine to give time for everything to power up first. This has become routine.
Why I began to do this? Goes back to when my truck was new to me. One time I was in a hurry, keyed on and immediately turned over the engine all in one quick motion and got a strange parking brake fault message. Have not seen any kind of fault message since.
Last edited by Russell Shettle; Jul 20, 2023 at 08:16 AM.
My daughter was driving it and indicated it was running a little rough. I'd just gotten the scan tool as a gift a couple weeks back and decided to see it it would be of any help. I know those codes were unrelated but was still concerned.
Not finding a long enough extension cord to connect my battery charger, I started the truck and moved it close to my car to create a proper voltage reading.
13.5V.
I started Forscan and checked the DTCs.
Just by starting the truck and driving a few meters, DTCs appeared:
SCCM B10AD:08-08
SCCM B1131:08-08
IPC U0140:00-08
and of course, U2100:46-8A.
I performed the procedure for the ABS module and a reboot. All procedures completed successfully without failure.
I went back to check the DTCs, and U2100:46-8A was still present. The others had disappeared.
I'm sure that if I restart the truck and drive a few meters, I'll get the SCCM and IPC DTCs again.
Perhaps IPC has a problem and is preventing the ABS module procedure.
I am beginning to think the Scanner 'use' is causing the confusion.
Not saying the Scanner is faulty, just when it's used within the test conditions that prevail at the time.
I have seen this happen before.
The SCCM codes are for two different functions as they are not able to be communicated with. They are not the issue.
First, don't do this within the first 5 minutes after start-up because the PCM is in diagnostic of the CATS that cannot be interrupted even during drive-away.
A way to tell when the CAT testing is complete is look at the Live Data only for Ignition Timing to drop into the 6 to 7 degrees range and the Idle drops back the 600 RPM range on the Tach or in Live data.
Also, the Battery is being Charged at higher current from the cranking drain of starting, especially multiple starting in a short period of time.
Power system down again and wait for more than 5 after restoring and start-up, >before doing any requested Testing.
This might or might not help, but worth a try.
Good luck.
Multiple Communication Code Issues
