gjp186

I get this code every 4th or 5th time I start the car. I get the 'Service Vehicle Soon' in the DIC and occassionally the Service Active Handling or ABS (once in awhile they stay lit on the IP until I restart the car) as well. But these NEVER appear while driving only on starting the car.

Codes as of right now:
PCM P1571 H
TCS No Comm. (was C1277 over the weekend)
SDM U1040 H C

Any help on these is appreciated.

2002 with 38K miles.

Thanks,

Gary

Aheash

From the IPC codes list available on this site, under tools > tech tips:

P1571 ASR Desired Torque -C
C1277 Requested Torque Signal CKT Malfunction
U1040 Loss of Communication with TCS

I'm sure someone else here can help you more from there than I can.

gjp186

Any ideas would be appreciated.

zeusoftexas

I have a 97 with the same problem. Hope someone can help both of us out?????

c0rv3tt01

Do we all have a similar problem

Ive done alot of reading, and even spent $100 to have Chevy throw in their 2 cents... Dealer says I need a new EBCM (Electronic Brake Control Module) which only costs about $1000.... Heh... "only" I crack myself up...

Im going to give this a shot this week.

http://forums.corvetteforum.com/show...875&forum_id=1

Cleaning the grounds can only help for future problems anyways, and if Im lucky it might even help me out... Hope this helps you guys out.

I also read a thread on here that mentioned somthing about a drain plug for the HVAC stopping up (located near the firewall) and causing moisture to back up to the BCM and cause failure, and a week ago I remember somone saying they found brake fluid inside their EBCM?

Either way you cant fix just a solenoid on the EBCM or anyhting like that, the whole unit has to be replaced from what I understand. Good luck to you guys, let me know how it turns out.

davette2000

if you need an ebtcm gmpartsdirect.com list for $274.75
part #9376711

Bill Curlee

The post that you are including is the one that I constructed a long time ago. I have a LOT of expierence with bad grounds, wet BCM EBTCM and have some information on batteries that may help.

The first thing that I recommend for anyone that is having lots of weird electrical issues is to remove the battery and take it into AutoZone, Advance Auto or Pepboys and have them battery checked out. Make sure that they check the reserve capacity of the battery and the voltage it supplies when there is a LOAD on the battery. If it drops below 10.5 volts, I would get a NEW battery!

The C5 electrical system is very sensitive to low system voltage!!! If you are seeing a lot of "U" series history "H" codes, there is a very good chance that those modules are turning off during the time that the engine is cranking (thus the "NO COMMS/ U series codes) As soon as the cranking load is removed from the battery, the system voltage rises above the threshold limits of the module and the module functions normaly. Put a meter on the battery terminals and have someone crank the car. If the voltage drops much lower than 11 volts, it will be needing replacing soon and could be causing you problems.

Some of the other low battery voltage symptoms are FOBS that require frequent "resyncing" DIC and ease entry functions that reset to stock settings.

While the battery is out, clean the battery cable connections and inspect for any acid spillage/leaks! Spray out the battery cable terminal with brake parts cleaner and then spray it out with WD-40. Reattach the battery cables to the battery and TORQUE the terminal bolts back on to 11 ft/lbs. This is a very important step.

There is a main ground connection on the passengers side of the engine just forward of and above the back of the starter. That connection needs to be clean and tight.


As for problems with EBCM and EBTCM, I guess that I am deep into that subject!!! Much much deeper than I ever care to have ever expierenced!!! To the tune of about $2000!!!

For those of you who have been following my fight with GM to repair my 30 day out of warranty Z06 with EBTCM failure, GM (SORT OF) pulled through and gave me a Voucher of $1600 towards a new GM car! I still have bloody knuckles over the fight that I had to put up to get them to honor the repairs that they stated that they would cover! (NO PROBLEM was the words out of the service reps mouth

After I got them to replace my EBTCM everything seemed FINE for about two months and it started throwing codes again! I purchased an 06 C6 last night and part of the deal was for the dealer to fix my 02 Z EBTCM issue. They called me today and reported that one of the female pins in the wiring harness was spread and not making good contact with the male pin. As soon as I find out which pin and what plug, I will pass that along. The SAD part about the entire deal was that I knew that the problem was a bad connection and recommended that to the Tech that he do a pull test on the female pins in all of the connectors. We will see what buying a $50,000 C6 will do towards a break on the repair of the problem!

davette2000

The price that you quoted on that module is correct ONLY on early C5 modules. 2001 and up modules are more like $850 - $900. Cars with AH require a smart EBTCM which is MORE money. Been there!

Grounds for the EBCM / EBTCM are critical!!! The motor solenoids and the relays for the EBTCM module need a good ground for the module and the system to function to operate properly! On 97 and early 98 C5 with a rear mounted EBTCM, the ground for that module is in Chassis Ground G-402, which is on the passengers side frame rail, in the rear wheel well area. It looks something like this:



Yours will most likely be a stud. Mine broke off and I had to replace it with a self tapping screw. That connection is subject to lots of nasty road stuff and will corrode easily. That wire goes to a ground connection on the EBTCM motor. The electrical ground on that motor is another place where corrosion will form. Be careful when removing the nut from the ground stud on the motor. It the stud turns inside the motor case, you can damage the entire motor and it will have to be replaced with a mew one!!!


On C5's with Front mounted EBTCM, the ground wire is on Chassis Ground G-101. Here is a picture of that ground connection:



The large single eyelet connection is the ground wire for the EBTCM! It is under the connection tab on the ground stud: You can see it in one of the pics below:





Bill Curlee

gjp186

Thank you for the reply. I'll check the grounds you suggest this weekend. Hopefully that will clear up the issue. The battery is almost 2 years old so maybe that may be the problem too. It sure seems an awful lot of us are having the same issue.

SDVette

I was having the same codes in my 98 (44K miles) 2 months ago. I tried Bill's advise (excellent advise, BTW) of cleaning the grounds but unfortunately it didn't fix the problem. I was out of warranty so I took it to a local vette shop with a good reputation, who systematically traced, inspected, and cleaned electrical connections until he found the problem. He billed me 10 hours @ $65/hr, so it was an expensive "repair", but it's been perfect since then.

These problem are becoming very common among C5s with some miles on them.

Good luck.

Fred

gjp186

I tested the voltage on cranking the engine. It dips to 10.67V then after the engine starts up to 14.1. Would this throw the No Comm. code?

The indicators on the IPC for ABS and Traction control are staying lit also.

MrEracer

I just completed a nasty diagnosis of the same codes and problem on a '97. In my case it was an intermitent loss of source voltage to the EBTCM. It was a harness problem, not the EBTCM. To solve the problem I had to run an alternate wire in place of the one that was bad. You may or may not have my exact problem, but check all your abs fuses and verify voltage to/from them as a starting point. Cleaning grounds would also be advised.
If you have access to the GM manuals there is a trouble shooting procedure there. Start with 'loss of comm.' on the TCM since that was the cause of the other delivered/requested torque codes (1571) that I had.
Shirl Dickey
SD Racing Enterprises
Aguila, AZ

gjp186

I checked the grounds once again, all looked good but I cleaned them and the grounding lug again. I also disconnected the battery during this process and after I reconnected it and started the car, all was right with the world. No codes, no 'Service Vehicle Soon'. Drove it a bit, started it a few times and nothing!

I get in this AM and they're back!!!!!!!!!!!! This is frustrating to say the least!

gjp186

The plot thickens.....out at lunch after clearing the codes. Start up 'Service Vehicle Soon' Trac control lit on IPC, ABS lit on IPC.

Drive to destination, get out. Get back in start up, SVS again, head back to work, take a hard left, ABS clears from IPC!!

Get back to work check codes:

PCM P 0135 C, P 0141 C, P 0155 C, P 1571 H, P1689 H C (????)

TCS C1277 H

Thoughts??

gjp186

ttt

This is happening randomly now. I can't seem to determie any clear patterns to the warnings.

Some days the car will be fine, and other days it will give me the error on EVERY start, and only on starting. It never gives me the warning after the car is started. Any ideas at all?

Bill Curlee

10.6 is LOW and wes it could cause the issue. Battery should be able to maintain at least 11 volts.

Try this! Use a set of jumper cables and parallel in a good battery. Start the car and measure the voltage during start up. If it maintains above 11 volts and your problem goes away, replace the battery.

Alot of the EBTCM female connectors are turning up BAD. They fail to maintain a tight connection on the male pin in the male connector! You need to check every female connector in all of the EBTCM harnesses.

Here is what one looks like. This one was BAD!!







Bill

gjp186

Bill:

Thank you for the tip, I'll give it a try. Hopefully I'll get it narrowed down.

Bill Curlee

One of the other Forum members that I have been helping had a problem with an intermitant TCS code issue (I think it was 1226) Here is what he found and he shows what a BAD and NEW connector look like!

Bad one is on the right



BC

gjp186

Where are these connectors located?

Bill Curlee

This one can be found on the harness that goes to each front wheel. The harness that plugs into that one is a short one anout 20" long and that one plugs into the wheel sensor.

BC

SteveDoten

maybe if was already covered, but GM has updated the harness that goes to the wheel sensors sometime in 2000 or 2001 model years, the harnesses where getting worn out w/ the suspension movement; my '99frc has harnesses w/ a build date of 2000, sometimes this fixes the problem