Talked to the dealer today. They searched all throughout the vehicle to find a bad part but they were unable to find any. The Corvette Tech came to the conclusion that it was a faulty connection between the ECM and PCM ( if I remember correctly). So they put some dielectric grease and connected them back up. They couldnt get it to throw any codes. Its still there because the warranty officer had to leave for a emergency or something. So I'm going to go and pick it up in the morning and drive it for a while to see if it'll throw any codes. I'm hoping that a faulty connection was all it was.

Has anyone else had these codes occur to them due to a simple faulty connection?

 

Well....at least they're working on it!!

I haven't had your problem, but I've read of numerous forum members that have had problems similar to yours. Although it appears that it's defective components, often it's just simply a connection of a cable, ground, or wire harness connector. So....hopefully that's all it is in your case - you just need to find the culprit connection.

As has been said before - hang in there! Once you get the problem figured out you'll love the features, handling, and performance of the car.

BTW, the abbreviations ECM (Engine Control Module) and PCM (Power Control Module) are used pretty much interchangeably (although some will argue that only one refers to the unit in the C6).

If what ever they did fixes things, try to find out fairly specifically what they did so you can offer it up for others to try in the future if they have a similar problem. That's the beauty of the forum, and it's very rewarding when you can help somebody out.

Good luck, and keep us informed.

Bob

 

Bob's right; it'd be a great help to find out exactly what was wrong, parts-wise. Also, didn't someone say they thought it was BCM (body control module), or was that from another thread?

 

I would insist on a BCM, TCM, ECM reflash while there. Cant hurt, takes little time and you would get any updates while you are at it. Could have a bad program in one of the modules

 

I doubt it was a cable connection. Good luck.

 

Subscribed for reference...........

 

Ok, so heres what they found.......its LONG. This past Saturday it starting coding so I went to the local Autozone (dealer/service dept was closed) and it read those to codes, the P0700 and that U0073 I think it was(its in the other thread). Anyways, I take it down and this is waht they found, this is the codes that were read.......WARNING FOR DIAL UP USERS!

Radio
U1017- Lost communication with engine
U1024- Lost comm with TCM
U1000- class 2 data link (trying to read his writing, which isnt great so bare with me with the mistakes).

Pass door module?
U1024-lost comm with TCM

EBCM
U2100-Connection are something BUS
C0161 sym 12- ABS/TCS Brake switch connection(not sure, can't read his writing)

DDM
U1024- Lost comm with TCM

VCIM
U1017- Lost comm with ECM
U1000- Class 2 data link

SIR
U1017- Lost comm with ECM
U1000- Class 2 data link

RCDL
U1024- lost comm with TCM
U1017- Lost comm with ECM
U1000-class 2 data link

PDM
U1017- Lost comm with ECM

Nuvi Radio(? again can't read his writing)
U1017 Lost Comm with ECM
U1000- Class 2 data link
U1024-lost comm with TCM

IPC
U1040- lost comm with EBCM
U1024- Lost comm with TCM
U1000-class 2 data link
U1017-lost comm with ECM

HVAC
U1000-class 2 data link
U1017-lost conn with ECM

HUD
U1040- lost conn with EBCM
U1017- lost conn with ECM
U1024- lost conn with TCM
U1000- Class 2 data link

ECM
U0073- Control Module Connection BUS

Drive Position Module(?)
U1024-Lost conn with TCM
U1017-Lost conn with ECM
U1064-LC with BCM
U1000-class 2 data link

DDM
B1420 Device using(?, bad writing, guessing)
U1017-lost conn with ECM

DRR(?)
U1017-lost conn with ECM
U1000- Class 2

ECM
P0700-TCM mil

Now, they checked every module and each was functioning properly. They checked grounds and those were good. They drove it yesterday to see if it would code and it didnt, I told them it happened in teh morning when it was cold. So they left it in a cold room inside there shop. I went to get it today, cranked it with no problems and drove it around for a bit with no more codes.

Now I can't read the writing very well so I'm going to do my best to write what the vette tech said on the shop print out......again please bare with me.

"Ran Diagnostic Scan, see attached see for trouble codes. Most codes are loss of communication with TCM and ECM. Checked GMLAN circuit(this is where I can't read his writing) se algith for short or OHM circuit has 60 ohms ok. No short to signal or 12 voles found. Applied Dielectric grease to connector C184, C180, ECM connector to At transmiision client code and test drive 15 miles, no codes reset.

ECM part # 12597121."

That is what was written, I spoke with the tech and he said he also checked the grounds and modules. REMEMBER, THOSE CODES ABOVE WERE ALL THE HISTORICAL CODES FROM 2 DAYS. Thats what I've gotten so far, but I will keep everyone posted to see if they pop up again. The Tech did say that he was following the servicing bulleting from GM on this issue. So if they do pop up, we will try step three etc.

 

nobody has anything to add to that? LOL I meant to add that I do have the car and I drove it this morning and it has been great so far. Fingers crossed and knock on wood!

 

Usually the problem with electronics is in the connections. Whether its in a car, aircraft, stereo, etc. That is why problems can sometimes go away just by unplugging and replugging a connector.

That is also why they spent so much time on the grounds, etc. Based on the number of communication U codes I would lean toward some sort of a problem with the battery, its connections or ground. If that is all good then it could be there is something wrong with the serial datalink. All of the modules talk to each other across that link. They continually send State of Health messages back and forth. If a module misses one of the messages it sets a U Code. However, if it receives the next SOH it will not reset the code. A few U codes are usually present on C5s/C6s and they don't mean much until there are a lot of them. In the diagnostic procedure for those codes you can see the emphasis on voltage, ground, connections:
DTC U1001-U1254

Circuit Description
Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. When a module receives a message for a critical operating parameter, the module records the identification number of the module which sent the message for State of Health monitoring. A critical operating parameter is one which, when not received, requires that the module use a default value for that parameter. Once an identification number is learned by a module, it will monitor for that module's Node Alive message. Each module on the class 2 serial data circuit which is powered and performing functions that require detection of a communications malfunction is required to send a Node Alive message every 2 seconds. When no message is detected from a learned identification number for 5-10 seconds, a DTC U1xxx where xxx is equal to the 3-digit identification number is set.
The control module ID number list below provides a method for determining which module is not communicating. A module with a class 2 serial data circuit malfunction or which loses power during the current ignition cycle will have a Loss of Communication DTC set by other modules that depend on information from that failed module. The modules that can communicate will set a DTC indicating the module that can not communicate. The following modules communicate on class 2 serial data circuit:
Control Module================================ ID Number
Body Control Module (BCM)======================= 064
Inflatable Restraint Sensing and Diagnostic Module (SDM)== 088
Instrument Panel Cluster (IPC)======================= 096
Head Up Display (HUD)=========================== 098
Radio=================================== ====== 128
Digital Radio Receiver (DRR)======================== 137
Communication Interface Module (OnStar®)============== 151
HVAC Control Module============================= 153
Driver Door Module (DDM)========================= 160
Passenger Door Module (PDM)======================= 161
Driver Door Switch (DDS) ========================== 164
Driver Position Module (DPM)======================== 166
Fold Top Controller (FTC)=========================== 177
Remote Control Door Lock Receiver (RCDLR)============= 193
Steering Column Lock Control Module (SCLCM)=========== 194

The BCM emulates some devices that are on high speed GMLAN serial data circuit to the modules on class 2 serial data circuit. The BCM transmits multiple Node Alive messages using source IDs that correspond to each of those high speed GMLAN nodes. This is in addition to the BCM behaving itself as a real node. The following module communicate on high speed GMLAN serial data circuit and are emulated by BCM on class 2 serial data circuit:
Control Module ==================== ID Number
Engine Control Module (ECM)=========== 017
Transmission Control Module (TCM) ====== 024
Electronic Brake Control Module (EBCM) == 040

When more than one Loss of Communication DTC is set in either one module or in several modules, diagnose the DTCs in the following order:

• Current DTCs before history DTCs unless told otherwise in the diagnostic table.
• The DTC which is reported the most times.
• From the lowest number DTC to the highest number DTC.

This vehicle has DTCs which include DTC Symptoms. For more information on DTC Symptoms, refer to DTC Symptom Description in Vehicle DTC Information.

Conditions for Running the DTC

• The following diagnostic trouble codes do not have a current status:
  • U1300
  • U1301
  • U1305
• The vehicle power mode requires serial data communication to occur.

Conditions for Setting the DTC
A node alive message has not been received from a module with a learned identification number within the last 5-10 seconds.

Action Taken When the DTC Sets
The module uses a default value for the missing parameter.

Conditions for Clearing the DTC

• A current DTC clears when the malfunction is no longer present.
• A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.

Diagnostic Aids

• An intermittent open between the inoperative module and a star connector may cause these codes.
• A poor connection at the inoperative module or a star connector may cause these codes.
• An intermittent open in a star connector may cause these codes.
• An improperly powered module may cause these codes.
• An improperly communication on the high speed GMLAN serial data circuit may cause these codes.

Test Description
The numbers below refer to the step numbers on the diagnostic table.
Step 2. A module that does not communicate in high speed GMLAN link may cause the setting of the class 2 DTCs.
Step 3. A module which loses power during an ignition cycle will cause other modules to set lost communication DTCs.
Step 4. A module which loses power during an ignition cycle will cause other modules to set lost communication DTCs.
Step 5. The malfunction is due to an open in the class 2 serial data circuit or an open in the module.
Step 9. The module which was not communicating may have set lost communication DTCs for those modules that it was monitoring.
Step 11. The modules which can communicate indicate the module which cannot communicate. You must clear the DTC from these modules to avoid future misdiagnosis.
Schematic Reference: Data Link Connector (DLC) Schematics
Connector End View Reference: Master Electrical Component List in Wiring Systems

Step 1
Did you perform the Diagnostic System Check - Vehicle?
Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

Step 2

• Install a scan tool.
• Turn ON the ignition, with the engine OFF.
• Record the DTCs set in by each module.

Did you record any DTCs in the range of U2105-U2177 or U0100-U0299?
Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information

Step 3
Important
Use the control module ID number list in order to determine which module is not communicating.
Test the following circuits of the module that is not communicating for an open or short to ground:

• The battery positive voltage circuits
• The ignition voltage circuits
• Battery positive voltage output circuits
• Switched battery positive voltage circuits

Refer to the following:

• Control Module References for the applicable schematic
• Circuit Testing in Wiring Systems
• Wiring Repairs in Wiring Systems

Did you find and correct the condition?

Step 4

• Turn OFF the ignition.
• Test the ground circuits of the module that is not communicating for an open. Refer to the following:
  • Control Module References for the applicable schematic
  • Circuit Testing in Wiring Systems
  • Wiring Repairs in Wiring Systems

Did you find and correct the condition?

Step 5

• Disconnect the star connector that is connected to the module that is not communicating.
• Inspect for poor connections at the star connectors. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Step 6
Test the class 2 serial data circuit of the module that is not communicating for an open between the module and the star connectors. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?

Step 7
Test the following circuits of the module that is not communicating for poor connections:

• The battery positive voltage circuits
• The ignition voltage circuits
• Battery positive voltage output circuits
• Switched battery positive voltage circuits
• Ground circuits
• Class 2 serial data circuit

Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?

Step 8
Replace the module which is not communicating. Refer to Control Module References for replacement, setup, and programming.
Did you complete the replacement?

Step 9

• Install a scan tool.
• Turn ON the ignition, with the engine OFF.
• Retrieve DTCs from the module which was not communicating.

Does the scan tool display any DTCs which do not begin with a "U"?
Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information

Step 10
Use the scan tool in order to clear the DTCs.
Did you complete the action?

Step 11
Retrieve DTCs from the modules which had the Lost Communication with XXX DTC set.
Does the scan tool display any DTCs which do not begin with a "U"?
Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information
Step 12

• Use the scan tool in order to clear the DTCs.
• Continue diagnosing or clearing the DTCs until all the modules have been diagnosed and all the DTCs have been cleared.

Did you complete the action?



The ABS problem may go away if the other problem can be found. It has to do with the voltage of the brake pedal position sensor which is sourced from the BCM.

C0161 12
Possible causes of this DTC are the following conditions:

• A signal circuit of the brake pedal position sensor is open.
• The brake pedal position sensor needs recalibration.
• All brake lamps are open.
• All brake lamp grounds are open.
• An internal brake pedal position sensor malfunction.

Bill

 

There is no reference to tcm codes. If the ecm has a p0700 stored it means the tcm requested the mil on due to a trans code/problem. The tech should scan the tcm for codes. If any module goes out it can reak havoc on the whole system. Has there ever been any work done on the trans? If there are no stored codesin the tcm then my money is on the tcm itself. See below
DTC P0700

Diagnostic Instructions



Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic approach.
Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor

DTC P0700: Transmission Control Module (TCM) Requested MIL Illumination.

Circuit/System Description

The transmission control module (TCM) uses the (GMLAN) to signal the engine control module (ECM) that the TCM is requesting malfunction indicator lamp (MIL) illumination. This happens when the TCM has determined that a failure affecting emissions has occurred in transmission control system. When the ECM receives the a message from the TCM, DTC P0700 will set.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

The TCM is requesting MIL illumination.

Action Taken When the DTC Sets

DTC P0700 is a Type A DTC.

Conditions for Clearing the MIL/DTC

DTC P0700 is a Type A DTC.

Diagnostic Aids

DTC P0700 can not be cleared from the ECM until the related TCM codes have been cleared.

 

Due to the fact that you do not have any TCM communication error codes listed, my money is on the TCM or the communication circuits leading to the TCM.

 

like I said before in the first thread, this is a Bus communication issue. I have had cars like this, and it can be very hard to track down the cause. It is most likely a particular control module on the bus pulling down bus communication. That is why there are so many different codes being set.

It looks to me that all the modules on the body-bus are registering fault codes that are showing a CAN-bus communication failure between powertrain control modules (ECM, TCM, etc.). I'd be looking very hard at all the power supply inputs to both control modules, as well as anything else on said CAN-bus. On a lot of cars, the ABS/stability control modules are also on this bus and could be causing a loss of communication.

The best way to track down a bus problem is to disconnect each module on the suspected bus one by one until communication is restored. This can be tough when the problem is intermittent. A bus that is permanently down is easy to fix, but one that is only down once in a while is not.

I think it is time for the dealership to replace some hard parts, not just fiddle with connections.

Andy

 

Same stuff like that happened to me. Can happen as simple as D/C and reconnecting the battery. Worry about it only if it is repeatable problem.

 

I posted this on the other thread just wanted to make sure you got it.
hope it helps. I have a 2007 Z06 with 14000 miles on it. I love this beast. Has you can see with the amount of miles on the car, I only take it out of the garage when the weather is nice. I drove the car to work the other day and when I got in the car to go home, I noticed the car security light came on. I turned the car off which usually resets this light. Well the car would not start. All the gages went dim and nothing on the starter. I turned the ignition off and opened and closed the door. This time the car started. When I started driving the security light came back on then the service active handling, service fuel system, traction control, service car soon. While I was driving home all the gauges went down to zero and the low fuel warning came on. I have had some of those errors before and was able to fix them by simply charging the battery. This time charging the battery did not fix the errors. I completely disconnected the battery, charged it, cleaned the terminals, and tightened them down good. Started the car and still had all the errors. I scanned it and got the U0073 error code that read bus disconnect. I remember reading on this forum that just one bad wire on a controller can cause all kinds of problems. So after exhausting all the usual, make sure all grounds are good and the battery is good and the terminals are tight, I disconnected the battery, pulled back the passenger carpet to expose the control modules and carefully disconnected the cable connectors to each of the three main controllers. I am not a fan of the metal used in these connectors and I wanted to make sure there was a good connection between all the pins by reseating the connectors. Well so far so good. Reconnected the battery started the car and no errors what so ever. Took the car for a good hard 100 mile spin and still looking good. I am back to enjoying this beautiful beast.

 

Check the ground wire in the REAR DRIVER's side wheel well.

Make sure it is clean. GentleBen (forum member) had a similar issue with his 2005 and it was traced to that GROUND WIRE!! TONS and tons of codes...

 

I wish I hadn't been reminded of the problem. The ground that Bluewasp was referring to was an intermittent ground that connects the BCM to the chassis. When connected everything was as it was supposed to be - but when the ground became loose all h*ll would break out. It began by sending codes between the BCM and ECM until, eventually, both units were overwhelmed by the numerous fault conditions and the ECM ordered the engine to shut down.

This occurred on a drive to the Cruise In and caused this problem four times at highway speeds. At that point, the quickest/easiest cure was to disconnect the battery for approximately 30 seconds to release the codes and continue the trip. When I got to Bowling Green I had the local Chevy dealer put a Tech II on the car. I was surprised to see that the car had codes for an inability to talk to the Nav unit (especially as the car does not have Nav), inability to control the F55 suspension (well, the car is equipped with a Z51 suspension so it should not be talking to something that is not installed) plus at least 20 other codes. Unfortunately, since the car had been highly modified (shown by the Lingenfelter fuel rail covers) the dealer refused to work on it all. I had the car shipped back to Northern Virginia and Bluewasp and I troubleshot the car to find and correct the problem. In all honesty, Bluewasp did suggest this to me while I was in Bowling Green but I had no way to lift the car to see if that was the problem or not. The problem turned out to be a missing nut on the grounding bolt. The wire was on the bolt but without the nut to hold it tight it was not always connecting to the chassis ground, thereby causing an intermittent connection.

Like Bluewasp suggested, I strongly agree, that based upon the symptoms described that it is a grounding issue and suspect it is actually with the BCM and not the ECM.

Let us know what you find please.

 

I am having the same issues with my 08. I did find a service bulletin from GM citing a loose pin on the transmission harness. It is at the shop right now. Will let everyone know what they find on mine.

 

Where exactly is this ground stud in the rear wheel well, I am experiencing simular problems!!!!

 

Look on the inside of the wheel well slightly behind and above the rear axle on the drivers side. The bolt sticks out parallel to the rear axle and you should see one wire coming from the rear fascia (just inside of where the rear lights would be if they extended through the fascia) to this bolt. Make sure the nut is tight as the wire can "float" on the bolt and give you all sorts of weird electrical gremlins.

 

I know that this is an old thread and there may be other info out there.
My 05 had the same issues. My clues were that it usually happened after a rain or dewy morning. Eventually I surmised that moisture was getting into one of the three connectors located between the battery and fender. Water can drip onto them from the hood joint. Though they have seals on the wires, I applied silicone sealant to the wires and housing joint on all three connectors. I haven't had any problems since doing that. It may not be pretty but it worked.