MIke D Posted July 16, 2008 Report Share Posted July 16, 2008 So I have now had these codes a few times in the last month... P1381 - Misfire Detected - No Communication with Brake Control Module and U1128 - Loss of Communications with IRC. First, what is the irc? I know of an ISC.... Second, where is the brake control module? could it be a lose plug or ground? Cop didn't see it, I didn't do it! 93 STS 225,000 Miles 99 STS 111,000 Miles Link to comment Share on other sites More sharing options...
Cadillac Jim Posted July 16, 2008 Report Share Posted July 16, 2008 The IRC is the Integrated Radio Chassis. That's where the chimes come from, and if you have a hands-free car phone or OnStar that's where the speakers for those are, too. The radio is controlled over the car's network, and it can output sound transmitted digitally over your car's network. If you don't have driving complaints and you don't get lights turned on or warning messages, and you never see these as Current, I wouldn't worry. It wouldn't hurt to check the wiring, though. These are both network-related issues so look for the purple wire and check to make sure than connectors with it are clean and tight. I would venture that the brake module is near the ABS pump, which is under the main maxifuse block behind the air cleaner. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
JimD Posted July 16, 2008 Report Share Posted July 16, 2008 ....Second, where is the brake control module?The 'brake control module' is married to the ABS pump and related plumbing and becomes the Electronic Brake and Traction Control Module (EBTCM) which is located at the bottom left front corner of the engine cradle.....could it be a lose plug or ground? That would be the first items I would be inspecting. Drive it for a while to deterine if you are setting a P1381 each and every drive cycle; read and clear the codes as often as you can. Perhaps another code will eventually be set that can provide another clue; and a big clue would be a "C" code related to EBTCM. Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
BodybyFisher Posted July 16, 2008 Report Share Posted July 16, 2008 You have been having a misfire. Did you ever do a compression test? Bumps and road conditions can set off a misfire code, and the PCM use input from teh EBTCM to diagnose the misfire. DTC P1381 Misfire Detected - No Communication with Brake Control Module Circuit Description This diagnostic test checks for the absence of serial data from the EBTCM. This data is needed for misfire diagnosis (DTC P0300). Conditions for Running the DTC DTC P0300 is set and is requesting the MIL ON. Conditions for Setting the DTC No serial data is received from the EBTCM for 1.6 seconds out of the last 2 seconds. Action Taken When the DTC Sets The Malfunction Indicator Lamp (MIL) will not illuminate. No message will be displayed. Conditions for Clearing the DTC A History DTC will clear after forty consecutive warm-up cycles with no failures of any non-emission related diagnostic test. A Last Test Failed (current) DTC will clear when the diagnostic runs and does not fail. Use a scan tool to clear DTCs. Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended. See this P1380 also for more understanding of what is going on DTC P1380 Misfire Detected - Rough Road Data Not Available Circuit Description This diagnostic DTC is used to determine when the EBTCM has lost the ability to provide rough road data to the PCM for misfire detection (DTC P0300). When the PCM sees this condition is present via serial data. DTC P1380 will set. Conditions for Running the DTC DTC P0300 is set and requesting the MIL ON. Conditions for Setting the DTC Rough road indicator not being sent by EBTCM for 1.6 seconds out of the last 2 seconds. Action Taken When the DTC Sets The Malfunction Indicator Lamp (MIL) will not illuminate. No message will be displayed. Conditions for Clearing the DTC A History DTC will clear after forty consecutive warm-up cycles with no failures of any non-emission related diagnostic test. A Last Test Failed (current) DTC will clear when the diagnostic runs and does not fail. Use a scan tool to clear DTCs. Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Clearing Diagnostic Trouble Codes in Powertrain Control Module (PCM) Description . Diagnostic Aids If this DTC is set along with DTC P0300, it may represent an invalid misfire due to a loss of rough road data. Several ABS system problems could cause a loss of rough road indication from the EBTCM. All ABS/TCS system problems and DTCs should be corrected first. Then duplicate the conditions under which DTC P1380 set and see if the problem reoccurs. Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
MIke D Posted July 19, 2008 Author Report Share Posted July 19, 2008 You have been having a misfire. Did you ever do a compression test? Not yet. I don"t have time off till august.. still trying to fix it withought going to pepboys or the stealership Cop didn't see it, I didn't do it! 93 STS 225,000 Miles 99 STS 111,000 Miles Link to comment Share on other sites More sharing options...
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