C5-JIM

U1016 loss of communications with PCM
U1064 ' ' ' ' BCM
U1096 ' ' ' ' IPC
These codes keep appearing. Does anyone have any suggestions where to start. I thought maybe grounds ? I would like to know if any one has had this problem if so what is the cure.
Thanks, Jim

STA-BLK

Im still getting these codes for the rfa as well and i cant find out why.The dealer says its normal.Any help would be great for the both of us!

X-ZZ4

I regularly see those as historicals on my car........

Richin Chicago

It is very common for C5s from 2000 back. I have heard that they upped the threshold trigger point after 2001 so these codes don't "false" any more but I have had them, off and on, since I bought my car (2000 hardtop).

6spd89

Would these false codes show up as NON-LOGGED data when doing a tune?? My tuner did not want to use his tune until this issue was not a prob. He was thinking my mass air was faulty. It is a 98.Not stealing the thread but i had these same codes after my attempt to tune w/HP tuner.
Matt

C5-JIM

Even throwing the codes before and after the tune the car runs like a bat out of h-ll.
Jim

jeff1surfs

It might be the tires pres. sensors?
I changed my rims and did not change sensors over, my car also still runs like a bat outa h#ll.
I recently began having an issue with the prompt "service engine soon" and the TC and ABS are disabled.
Still researching that.
Good Luck
Jeff

tdahl

have the same thing on my 99FRC. It did happen EVERY time i drove the car, once first thing then two or three times during a drive. Did find a loose battery cable on the NEG (Exide Oribital) as the internal nut bottomed out and the cable never was snug. Replaced with red top (fresh battery) now have a tight connection on the NEG to the battery, and followed Bill Curleys advise on the grounds as far as locating, cleaning and coating with dielectric (sp?) grease. I have only had Service Vehicle Soon twice in about 50 runs this year. Do see "loss of communication" codes however nothing current, only history. So in the end, I have seen results on my car from securing, cleaning and coating the electrical points under the hood of the car.

runamuk

It's common to all C5's, I don't know for a fact but if I were to guess then:

The computers on the C5 require a certain voltage to operate and if the voltage drops below a preset limit then it will tripper a loss of communication with the other modules, this drop in voltage happens when the car is started and the draw on the starter uses a large amount of amperage.

If your car is not experincing any messages like "service vehicle soon" and no warning lights are illuminating then disregard these codes.

6spd89

So, I assume it is prob. safe to tune then?? I have no SES light or anything else. I cleared them the other day and it has not returned.I also removed 2 fuses relating to the comp. for about 5min. I think it was #23(10amp) and #26?(10amp). Drove just fine.
Matt

ramsvette

99 C5 corvette U1016 Loss of Communications with PCM once I turn the key dash cluster blinks on and off for about five minutes then it will start but once I turn it off I have to go through the same steps - have cleaned three major ground connects under the hood - can anyone help

C5 Diag

So are you saying the cluster will blink for 5 minutes and THEN the engine will start ??...while the cluster is blinking the car will not start ??...is this correct ??
Basically these "U" codes are "finger pointing" codes..."YOU,YOU,YOU !!...it is usually NOT the module that has the U code in it that is giving you the problem !!...your IPC and PCM aren't communicating !!

EDIT: BTW the ground for the IPC is NOT under the hood...on my 2001 the ground goes into a splice pack (SP208) which is on the R/H side of the IPC...that splice pack is then grounded at G104 which is on the R/H frame rail below the battery tray...there looks to be another ground which goes into SP201 which is on the IP harness and then it grounds to G201 which is about 13 inches from the HVAC control head connector !!.....AND GET YOUR BATTERY TESTED !!

ramsvette

Thanks Ill go check this out right now