I tried upgrading my ecm via a tech 2 and it will not communicate with it. I can barely read codes. I took everything off the truck as far as programmers and such with no luck in communicating with it. My service 4wd light just came on and I don't know how to explain to the dealer my problem with out them charging me for a new ecm or thinking I might of shorted it out

if you end up needing an ecm check out ebay can get a decent deal on there sometimes

Unplug your ECM and let it sit for an hour.

Now try to start your truck. If it doesn't start, try to communicate with the ECM using a Tech II or Predator or AutoTap.

If still nothing, what do you think might have caused it?

now what was that about smoking me nowhttp://www.dieselplace.com/forum/images/smilies/hihi.gif



















http://www.dieselplace.com/forum/images/smilies/joke.gif good luck with it

What year truck? 2003 or newer? Any stereo or alarm add ons?



I tried upgrading my ecm via a tech 2 and it will not communicate with it. I can barely read codes. I took everything off the truck as far as programmers and such with no luck in communicating with it. My service 4wd light just came on and I don't know how to explain to the dealer my problem with out them charging me for a new ecm or thinking I might of shorted it out

A signature would help. My dealer replaced mine under warranty.

Unplug your ECM and let it sit for an hour.

Now try to start your truck. If it doesn't start, try to communicate with the ECM using a Tech II or Predator or AutoTap.

If still nothing, what do you think might have caused it?
I don't know what might of caused it... We tried many times with a tech II and it just said "couldn't communicate with ecm. Then, we took the ecm completely out and put it on the bench and tried to communicate with it from an actual computer to reprogram it and no dice. The only thing I can really lean on is perhaps when I had Banks six gun installed, could it of locked it up maybe? (Banks is in the garage as of 2 months ago)

Which tuner are you using?



I dunno but if I buy anouther truck that's what I'm getting CC/LB.

Nice !! :thumb:

now what was that about smoking me nowhttp://www.dieselplace.com/forum/images/smilies/hihi.gif

http://www.dieselplace.com/forum/images/smilies/joke.gif good luck with it

:funnypost haha well... a little technical difficulty that will soon be figured out and once taken care it will be kickin a$$ again!!!

A signature would help. My dealer replaced mine under warranty.:badidea:
2003 Chevy 2500HD LT Dmax/Alli LB7 4x4 CC
AFE Stage 2 Intake, 4" Magna flow, PPE Hot Xcelerator, Propane PowerShot 2000 (currently changing to NOS),Allison stage 4 rebuild, 12" Cognito lift, 37" Toyo M/T on Weld Evo wheels,8 Bilstein oil reservoir shocks, regeared to 4.56 with eaton e-locker front and rear, Alpine iva-d901,Alpine DVD Nav system, Alpine XM tuner w/factory antenna,Alpine IPOD tuner, Kicker 800.4 for Cerwin-Vega competition mids and highs, Orion 275G4 running at 1 ohm pushing 4 Kicker L7 8" solo barics subs, front and rear corner strobes, wig-wags in the headlights

I wouldn't think the Banks would have anything to do with it being plug and play.I would check all connections particularly the ones where the Banks was disconnected.Confirm that all pins are making good contact and not backed out.

When you say benched,does that mean at the GM dealer?

Which tuner are you using?



I dunno but if I buy anouther truck that's what I'm getting CC/LB.

Nice !! :thumb:
Thank you ):h I took banks out and de-tuned the truck so it is completely stock at this time as far ecm goes. I going to call Banks today and see if the can remedy this problem for me as they are only 25 min. away if not go to dealership today and tell them my service 4wd light on the dic is popping up and let them hook up a tech II and watch it not work.

I wouldn't think the Banks would have anything to do with it being plug and play.I would check all connections particularly the ones where the Banks was disconnected.Confirm that all pins are making good contact and not backed out.

When you say benched,does that mean at the GM dealer?No it was at PPE location and all connections were rectified just to make sure that nothing was loose or had some dirt inside not making good connection.

Good luck figuring it out. I had a similar problem in my truck I couldn't load a quad program on mine. Talk about frustrating. I never did figure out the problem I just ended up getting a tts with a new ecm and everything. Once you have it figured out let us know so I can get my stock ecm fixed. Good luck.

After adding the "Soundgate" XM adapter to my 2003 truck by plugging in an additional "T" type wiring harness, I had trouble loading up my Quad program. It locked up many times:( until Diesel Tech told me to unplug the XM adapter. After unplugging the XM adapter the Quad loaded up the first time. :)

He then explained to me what was happening during the reload. I'll regurgitate -:t some of that later in the post.

Also, intermittent trouble with the Tech 2 when the Xm adapter is plugged in. Sometimes it works just fine and other times it will lose communication with the PCM. The 03's and beyond run alot of communication traffic on the bus.

Begin regurgitation...-:t

IMHO, lets assume your reflashing your PCM and during the reflash a signal is sent out to verify the stereo/alarm/theft status and it doesn't get the signal back it was looking for, at which time it aborts the load. Some programmers rewrite only certain parts of the code, and some rewrite all or most of it. If the abort happened at just the right time, you could effectively end up with an empty or corrupt PCM, thereby losing the ability to establish communication. It's like losing or corrupting the Bios on your desktop. The computer or in this case the PCM no longer contains the instructions to communicate with the outside world. :(

End regurgitation. :p:


I'm sure that PPE, being a stereo shop as well as a competent PCM tuning facility is aware of the 03 and beyond stereo/PCM mutual reliance upon one and other.

Then again the preceding :rant: could just be the result of inhaling way too much diesel smoke. :D


At any rate, I hope this helps you or someone else in the future. For 03 and beyond with modified stereo's you may want to consider having a second PCM or having your PCMs bench loaded and then install them in the truck.

you may want to consider having a second PCM or having your PCMs bench loaded and then install them in the truck.
So its actually a bad thing then having everything I have in my truck due to it possibly shorting out the ecm? And if I want to run the programmer then I should take into the shop and have them program the ecm directly on their bench to avoid any problem?

Well I called Banks today and their tech support basically told me to pound sand. He says that it is a physical impossibility for Banks to lock out the ecm. So on that note I guess the next step is going to the dealer tomorrow and face reality. I will keep posting as info comes my way

i don't see how their module would lock out your PCM. what was the last program you loaded into it? my guess is that is where your problem lies, even if you were able to remove it. if you took it to PPE i would think they could recover the ecm if its corrupted. i know Diesel Tech can.

In your first post:


I tried "upgrading" my ecm via a tech 2 and it will not communicate with it.

I'm thinking this is when the PCM lost it's mind. :(

But if you upgraded with a Tech2, you would have to use TIS2000 to get the upgraded calibrations, right? If you have a tech2 and tis then you have the same stuff the dealer has. You mean PPE loaded the Tech2 and tried to upgrade your PCM? Does the engine run with this PCM or is it wiped out? The service4wd message always displays for a little while when doing a reprogram.

i don't see how their module would lock out your PCM. what was the last program you loaded into it? my guess is that is where your problem lies, even if you were able to remove it. if you took it to PPE i would think they could recover the ecm if its corrupted. i know Diesel Tech can.
It was a stock ecm, then came banks, the PPE. The problem arose right after banks was installed. We pulled the ecm out at PPE and tried hooking it up directlyto the pc and it just would not communicate with it.

But if you upgraded with a Tech2, you would have to use TIS2000 to get the upgraded calibrations, right? If you have a tech2 and tis then you have the same stuff the dealer has. You mean PPE loaded the Tech2 and tried to upgrade your PCM? Does the engine run with this PCM or is it wiped out? The service4wd message always displays for a little while when doing a reprogram.
The exact thing the dealer has PPE has, and yes the engine runs just fine, its just I can't even pull DTC off the dam thing. It won't let the tech2 nor the xcelerator read or write to the ecm. The reason the 4wd light is an issue for me is because I had to take the truck in numerous times until they finally changed the encoder motor in the front diff or t-case.

I don't think theres anything wrong with the PCM. Its communicating with the other modules and sensors ok, just not the Tech2.

Have you checked the fuses??
yes in fact i double checked all the connections under the hood and anything that banks hooked into

It's a dam mind boggling thing

Good luck with it... sounds like you definately tried a few things.

Document ID# 826345
2003 Chevrolet Chevy C Silverado - 2WD


--------------------------------------------------------------------------------

Scan Tool Does Not Communicate with Class 2 Device
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. Connecting a scan tool to the DLC allows communication with the modules for diagnostic purposes. DTCs may be set due to this symptom and during this diagnostic procedure. Complete the diagnostic procedure in order to ensure all the DTCs are diagnosed and cleared from memory.

Diagnostic Aids
• The BCM detects that the ignition is ON and sends the appropriate power mode message to the other modules. Therefore, the BCM must be connected to the DLC for any other module to communicate with the scan tool.

• When the class 2 serial data circuit:

- is shorted to ground

- is shorted to voltage

The following DTCs may set:

• U1300

• U1301

• U1305

Test Description
The numbers below refer to the step numbers on the diagnostic table.

A partial loss of communication in the class 2 serial data circuit uses a different procedure than a total loss of communication of the class 2 serial data circuit.

The following DTCs may be retrieved with a history status. These DTCs are not the cause of the present condition.

- U1300

- U1301

- U1305

A State of Health DTC with a history status may be present along with a U1000 or U1255 with a current status. This indicates that the malfunction occurred when the ignition was on.

Normal class 2 serial data communication cannot take place until the body control module (BCM) module sends the appropriate power mode message. If the BCM does not send a wake-up message, other modules on the class 2 serial data circuit may not communicate.

Normal class 2 serial data communication cannot take place until the body control module (BCM) module sends the appropriate power mode message. If the BCM does not send a wake-up message, other modules on the class 2 serial data circuit may not communicate.

Normal class 2 serial data communication cannot take place until the body control module (BCM) module sends the appropriate power mode message. If the BCM does not send a wake-up message, other modules on the class 2 serial data circuit may not communicate.

If there are no current DTCs that begin with the letter "U", the communication concern has been repaired.

The communication concern may have prevented diagnosis of the customer complaint.

Step
Action
Yes
No

Schematic Reference: Data Link Connector (DLC) Schematics

Connector End View Reference: Master Electrical Component List and Inline Harness Connector End Views

1
Does the scan tool power up?
Go to Step 2
Go to Scan Tool Does Not Power Up

2
Turn ON the ignition, with the engine OFF.
Attempt to communicate with each module on the class 2 serial data circuit.
Does the scan tool communicate with any module on the class 2 serial data circuit?
Go to Step 3
Go to Step 8

3
Select the Display DTCs function for each module. If using a Tech 2, use the Class 2 DTC Check feature in order to determine which modules do have DTCs set.
Record all of the displayed DTCs, the DTC status and the module which set the DTC.
Did you record any DTCs in the range of U1000 to U1305?
Go to Step 4
Go to Step 7

4
Are history DTCs U1300, U1301 or U1305 retrieved from any module?
Go to Step 5
Go to Step 6

5
Important:: Turn ON the ignition, with the engine OFF, when testing for a short to voltage. Use the DMM MIN/MAX function to capture intermittent conditions.


Test the class 2 serial data circuit for an intermittent short to ground or an intermittent short to voltage. Refer to the following in Wiring Systems:

• Testing for Intermittent Conditions and Poor Connections

• Circuit Testing

• Connector Repairs

• Wiring Repairs

Did you find and correct the condition?
Go to Step 18
Go to Step 6

6
Are U1000 or U1255 the only DTCs displayed in the previously specified range?
Go to DTC U1000 and U1255
Go to DTC U1001-U1254

7
Diagnose the non communicating module by using the DTC U1001--U1254 Lost Communications with XXX procedure for the module which is not communicating. The DTC U1001--U1254 Lost Communications with XXX procedure will determine which module is not communicating. Refer to DTC U1001-U1254 .

Did you complete the action?
Go to Control Module References in Body Control System for the applicable Diagnostic System Check
--

8
Turn OFF the ignition.
Disconnect the scan tool from the data link connector (DLC).
Inspect for poor connections and terminal tension at the DLC. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?
Go to Control Module References in Body Control System for the applicable Diagnostic System Check
Go to Step 9

9
Test the signal ground circuits of the DLC for an open or high resistance. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?
Go to Control Module References in Body Control System for the applicable Diagnostic System Check
Go to Step 10

10
Isolate the body control module (BCM) module from all other modules on the class 2 serial data circuit.
Attempt to communicate with the BCM.
Does the scan tool communicate with the BCM?
Go to Step 12
Go to Step 11

11
Test both class 2 serial data circuits to the BCM for the following conditions. Turn ON the ignition when testing for a short to voltage:
- High resistance

- An open

- Short to ground

- Short to voltage

Test the following circuits of the BCM for an open or high resistance:
- The battery positive voltage input circuits

- The battery positive voltage output circuits

- The ignition voltage input circuits

- The ignition voltage output circuits

- The switched battery positive voltage supply circuits

- The ground circuits

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?
Go to Step 18
Go to Step 16

12
Important: The BCM must remain connected to the DLC. Use the appropriate jumper if needed.


Connect the previously disconnected modules.
Starting with the splice pack furthest from the DLC. Perform the following for each splice pack, in order to determine the location of the concern:
Turn OFF the ignition.
One at a time disconnect each splice pack which connects the modules to the class 2 serial data circuit, by removing the splice pack comb.
Turn ON the ignition, with the engine OFF.
Attempt to communicate with any module still connected to the class 2 serial data circuit after disconnecting each splice pack.
Does the scan tool communicate with any module still connected to the class 2 serial data circuit after all the splice packs have been disconnected?
Go to Step 13
Go to Step 14

13
Important: The BCM must remain connected to the DLC. Use the appropriate jumper if needed.


Using the appropriate jumper at the suspect splice pack, perform the following in order to determine which class 2 serial data circuit or module is causing the concern:

Turn ON the ignition, with the engine OFF.
Using the appropriate jumper. Connect each previously disconnected module to the class 2 serial data circuit one at a time until communication with the class 2 serial data circuit is lost.
Did you complete the action?
Go to Step 15
--

14
Repair short to ground or voltage condition in the class 2 serial data circuits or in-line connectors to the last module connected in the branch being diagnosed. Refer to Wiring Repairs and Connector Repairs in Wiring Systems.

Did you complete the repair?
Go to Step 18
--

15
Test the class 2 serial data circuits to the suspect module for a short to ground or a short to voltage.

Turn ON the ignition, with the engine OFF when testing for a short to voltage.

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?
Go to Step 18
Go to Step 16

16
Inspect for poor connections and terminal tension at the harness connector of the suspect module. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?
Go to Step 18
Go to Step 17

17
Important: Perform the module setup procedure if required. Refer to Control Module References in Body Control System.


Replace the suspect module. Refer to Control Module References in Body Control System for the appropriate Repair Instructions for module replacement.

Did you complete the replacement?
Go to Step 18
--

18
Connect all of the modules.
Connect all the connectors.
Install a scan tool.
Turn ON the ignition leaving the engine OFF.
Important: The scan tool may require a power up reset before communication will occur due to a short on the class 2 serial data circuit. Turn off or disconnect the scan tool before you display DTCs.


Wait for 10 seconds.
Select the display DTCs function for each module. If using a Tech 2, use the Class 2 DTC Check feature in order to determine which modules do have DTCs set.
Record all of the displayed DTCs and the DTC status.
Did your record any DTCs which begin with a letter "U" and with a current status?
Go to Step 20
Go to Step 19

19
Did you record any DTCs which do not begin with a letter "U"?
Go to Step 20
Go to Step 21

20
Diagnose the DTCs as directed by the diagnostic procedures for the particular module or concern.

Did you complete the action?
Go to Step 21
--

21
Did you diagnose all of the DTCs?
Go to Step 22
Go to Step 20

22
Clear the DTCs using the scan tool.

Did you complete the action?
Go to Control Module References in Body Control System for the applicable Diagnostic System Check

BINGO! BCM problem because of an alarm or stereo stuff, typically speaking. Seen it before..........
The BCM detects that the ignition is ON and sends the appropriate power mode message to the other modules. Therefore, the BCM must be connected to the DLC for any other module to communicate with the scan tool.

The Tech2 doesn't "see" the PCM to communicate with it. You would need to "ping" it with a Tech2 to verify that it is, or is not "seeing" it. But what the hell do I know???!! I don't even make my own power boxes or programs!! LOL

Sorry, I was under the impression that the PCM was dead. I didn't realize the truck still ran.

Document ID# 826345
2003 Chevrolet Chevy C Silverado - 2WD
socaldiesel you're the man...their is one question though. does it matter if its a k2500 4wd? And also is their a way for the dealership of finding out what caused this condition for the ecm to do this? perhaps blame it on some of my electronics in the truck?

Doesn't matter 2wd or 4wd, the document would be the same. Dealer will probably say its because of the aftermarket stuff, and it probably is. I'm surprised they couldn't fix it for you at PPE, its not a big deal. If they installed your stereo stuff too, then it should be even easier to find out what is wrong.