EZGone

We are trying to tune the car and unable to do so.

Tech II and HP Tuners fail to communicate. They can pull down a few of the codes and read the specs(year, vin, 5.7L, etc) on the car then it fails when trying to go further.

My good friend will be commenting below to explain the failure to communicate points on the Tech II and HP Tuners. Based on the fact that we get some very basic communication before failure, I figure that the OBDII port is not the issue. But am willing to try whatever to get this problem solved.

What we know:
Car starts without issue.
2002 convertible with 32k miles
Complete drive train removed and replaced.
Texas Speed Built motor
MN12 transmission
Long tubes and X pipe
Wideband
No rear 02’s.

What we have tried replacing to fix the communication failure:
Replaced BCM and ignition with matching numbers.
Replaced PCM out of a 2002 coupe.
Charging the battery for extended periods of time.

I do have access to most modules and other parts required for troubleshooting. I own VetteVillains where we part out C5’s. This car came to us with a rod through the block so we decided to keep it and build it. Just having trouble with communicating through the OBDII port at this point.

With your help we hope to be able to get this beast tuned. Thanks in advance!

Brian

Steeldragon

I fought this once while tuning on a pulling engine using electromotive electronics. Turned out to be a problem related to the laptop. Actually the 9 pin interface that the laptop connected to. The laptop was a brand new Hewlet Packard and never did get it to work. Finally switched to an antique Vaio that didn't need the interface for the 232 connector and it was instant connect. I'm sure there's smarter people on here than me but something to look at.

EZGone

Thanks for the reply. And I hear you, We were hopeful that it may have been the problem at first. Unfortunately the Lap top nor the Tech II can communicate. And the Laptop Works on the other vehicles including another C5. So I think we ruled that out but you just never know.

Thanks for getting the ball rolling on this topic.

K-Spaz

For the most part the codes we saw were meaningless. The DIC does say Reduced Engine Power, Traction Control bla bla bla, Active Handling Bla Bla, basically it goes through every one of the systems and dings and complains. But the car starts normally and accepts throttle normally. Indicating tome I thought, a problem with the serial bus. I've read some about that here but never really paid much attention cause it didn't affect my car.

At one point I had 4 codes which were the std loss of comms, 02s missing, etc. I cleared those to get a clean picture. After messing around some and restarting, it had no codes. This was confirmed on both HPT and with the Tech2.

Last night while messing around replacing the PCM and BCM, we got the P1631 Theft Deterrent System Password Incorrect, but again, that's to be expected. Another code referred to the Vats, I didn't even mark these down because they were completely innocuous given what we were doing with swapping out the PCM, ignition switch and BCM.

I left before it got too involved last night, expecting to do some reading both here and in the service manual. I recommended checking grounds and asking here. What fuses we checked all were fine.

The car does ring the bell an awful lot. Any time the door is open it dings. Also, the RF headlight pops up and come on all by it's lonesome. No light switch required.

There is some question as to the car being a flood car or not. Most indications point to no. There was a mildew smell in the passengers footwell. I wasn't the one looking there to tell how bad that was, but from what I in there, it wasn't very serious.

Gordy M

Couple of questions. Have you performed the CASE learn yet to mate the crank to the pcm? Is the Tune file (OS) the same one as before or did you load the new OS using a bench harness?

v6turbo87

Total long shot here, but I remember reading that there is a serial data line that runs inside of the black accordion conduits at each door hinge. Bill C found a wire that backs out of a connector and screws up serial data communications. Pull back the conduits and check the wiring to the connectors.

EZGone

Thanks for the reply,

Do you have more information on what wire/plug, which door?

Thanks again

EZGone

No case learn to mate pcm/crank has been done to my knowledge. I don't think we can get enough communication to get that completed. The Tune File(on both PCM's tested/installed) is that of a stock C5.

I hope this answers your questions so far.

v6turbo87

https://www.corvetteforum.com/forums...ndow-inop.html


Read through this. I may be wrong and the wire only affects the door modules but further down in the thread someone mentioned that it cased other issues. Like I said, a long shot.

EZGone

I'll definitely read through it.

EZGone

I'm going to look into the bare wires on the doors this evening. Certainly seems like a plausible cause to my issue.

Greg_E

If there was water in the passenger foot well, it might be be worthwhile to take a look at the data star connectors for the class 2 serial bus.

You have probably already checked this, but have you checked the connections at the DLC port where you plug in the Tech 2 and Laptop?

When checking the door connectors don't get thrown off by the bare wire with the clear plastic tube over it. That is a ground for the speakers.
Go to post #57 and #58 by Bill Curlee. https://www.corvetteforum.com/forums...ndow-inop.html

If one headlight and door is malfunctioning check the headlight door module. I remember reading a post by 8VETTE7 stating that they can split and get water inside causing problems.

EZGone

We are going to look into these today for sure. We did find a bunch of speaker wires running throughout the car that were causing several power draws. We removed them all. We still have a power draw somewhere but have found there to be shorts in the radio and cluster. we will be swapping the cluster out and running some tests today for other power draws. Thanks for the help so far everyone.

Greg_E

Here is a video showing how to use the Tech 2 and Serial Data Link Tester to troubleshoot communication issues. If you can't get the issue resolved, you can pick up the Serial data link Tester on Ebay for about $100. They had several listed. I know K-Spaz already has the Tech 2.

Here is the same troubleshooting procedure as the video, presented as a magazine article.
http://mastertechmag.com/pdf/2010/08...iagnostics.pdf

EZGone

I bought the link tester after watching the video several times. I have no doubt that it will help isolate the problem and help get this issue solved.

It won't arrive until next week. Oddly enough... I'm excited to get it.

I'm going to get it fixed or I'm going to learn a few things... hopefully both though.

Thanks again.

Greg_E

There are some good troubleshooting tips in this thread.
https://www.corvetteforum.com/forums...etc-video.html

Here is another good one.
https://www.corvetteforum.com/forums...tcs-etc-2.html
(Once again, disregard the reference to the exposed bare wire in the door connector. It is the speaker ground wire. Unfortunately that image got copied to many threads.)
As mentioned in this thread you can remove star connector 2 and disconnect any module on that circuit. If comms. return you have narrowed down your search.

EZGone

I want to say thanks for everyone for the input. I was able to solve the no communication problem. The EBCM was the problem. I replaced the EBCM and communication was restored.

Finding the solution... (good read to cost effectively test each module on the serial data bus)

After using the serial data link connector with the Tech II we realized that there were a lot of codes that seemed to be linking to multiple sources. But the fact that isolating each module was allowing us communication gave us hope. However there was no "aha" moment when isolating the EBCM with the data link connector(selecting E on the data link connector).

In the video above you will see they cut the wires to remove certain modules from the serial bus to see if communication is restored with that module removed from the bus. I used this same concept to remove each module one at a time. But I did not cut the wire. The star connector cap "prongs" that slide into the plug are malleable and were able to be bent out of position and back in position without breaking. Slow and steady. The prongs easily pull out of the cap allowing for me to do the following.

I bent the prong to the 1st wire on the plug, as to remove that wire from the circuit, and attempted to get communication. Still no communication with the Tech II. So I flipped the prongs 180 degrees while leaving that same 1st prong bent. Allowing me to test the the last(12th) wire on the plug. No communication. So I bent that prong straight and individually tested the 2nd and 11th wires on the plug. No communication. The 3rd and 10th slots on the plug are empty. So I tested the 4th and 9th wires. No communication. So I removed the 5th wire from the circuit and magically communication was restored.

I then straightened the prong on the cap and tried to get communication. Communication was lost again. So I isolated it to that wire which was the EBCM. I then unplugged the EBCM and tried for communication(hoping the short was in the EBCM and not in the wiring to it). And with the EBCM unplugged I had communication. I pulled a replacement EBCM off the shelf and plugged it in. And I still had communication. Low and behold I was now certain the EBCM has a short within itself.

I completed the replacement EBCM install and still had communication. Problem solved.

Sorry for the long reply... I just wanted to explain it so others can easily test each module individually much like I did.

K-Spaz... get down here and tune this beast!

Again, thanks for the help everyone. All the ideas helped in some way as we eliminated certain problematic areas.

Brian

Greg_E

Glad to see you got the problem resolved, and thanks for posting the steps to get it fixed.

Smoken1

Glad to see you got it fixed. Still I find it odd that you had no codes for the EBCM

EZGone

I didn't have any codes at all. I had zero communication until hooking up the kent moore tool. My experience with the kent moore tool and the Tech II is very limited, so I really had no idea what I was looking for. After using them together I had tons of codes and no idea where to start.

So I decided to further isolate the problem using the star connector cap.