jhiiidoc

Got my car from the body shop where they informed me they had to replace my battery after having the car for 3 months (I think they killed it while working on it, but that is another issue). After the new battery install, the Service Traction Control and Service Engine Soon messages keep coming up in the DIC as well as lighting up the dash. Predator programmer says error code P1571 Traction Control PWM Link. I did get the occasional Service ABS/Traction Control message, which would reset after shutting off the engine and restarting, but never this. I have replaced the EBCM before (under warranty with another POS Delco Unit from GM), but I could always reset it. This one won't.

Most of the searches in the forum on this error code tie it to the EBCM, but usually it is associated with other codes. Am I safe in assuming the EBCM is bad again with only the P1571 code showing, or what might I check (besides the ground point...already cleaned that one with no joy).

Need help from the gurus of the Forum.

minitech

Do you have a 1997? If so you cou.d get that code and it is not possible to clear it.

jhiiidoc

2002 A4, non-pop up headlights, led mod fr/rr, HIDs.

Bill Curlee

You don’t need no stinking predator to read and clear DTCs

The DTC that you have is actually: Traction Control Torque Request Circuit and frequently happens when some other EBTCM or BCM error DTC is present. That predator wont show you ALL the BCM or EBTCM DTC.

Try this. Its more accurate and easier.

READING YOUR Engine Diagnostic Trouble Codes (DTC)

This procedure should be carried out any time you experience a problem with your C5. Most inexpensive store bought aftermarket code readers will ONLY read power train DTC’s. Reading the DTC’s with the C5 built in code reader will allow you to read ALL the modules in the vehicle.


READING YOUR Engine Diagnostic Trouble Codes (DTC)

This procedure should be carried out any time you experience a problem with your C5. Most inexpensive store bought aftermarket code readers will ONLY read power train DTC’s. Reading the DTC’s with the C5 built in code reader will allow you to read ALL the modules in the vehicle.

The Diagnostic Display Mode is entered with the following procedure:
1) Turn on the ignition but don't start the engine.
2) Press the RESET button to turn off any warning messages. (i.e. door open, trunk open ect)
3) Press and hold the OPTIONS button
4) While holding OPTIONS, press FUEL button four times within a 10 -second period.

Initially, the on-board diagnostics go into an Automatic Mode which will cycle through each module and shows diagnostic codes in a pre-set sequence: PCM - TCS - RTD - BCM - IPC - RADIO - HVAC - LDCM - RDCM - SCM - RFA. All codes will be displayed for each module. ( i.e. PCM = 4 codes) If none are present in a given module, you will see No More Codes on the display.

There are two types of diagnostic codes, Current and History designated with a letter suffix, “C” or “H”. A current code indicates a malfunction is present in the module displaying data. A history code indicates a problem existed sometime in the last 40 or 50 ignition cycles. When not accompanied by a current code of the same number, it's potential evidence of a previous problem, now resolved, that was not removed by clearing the codes. More likely it's an indication of an intermittent malfunction.

Intermittent codes are the most challenging of the diagnostics. An intermittent code may have happened once, may have happened more than once but is inconsistent or may be happening on a regular basis but not at the time the codes are displayed. History codes can also be caused by a current malfunction in a system that is not operating at the time codes are displayed. An example is the rear window defogger which doesn't operate until the Body Control Module detects engine rpm. For history codes set by a module that does not operate with the key on and engine off, a special diagnostic tool called a Scan Tester is necessary to properly diagnose the malfunction.

Once the system has displayed all modules, it goes into the manual mode which allows selection of each module using combinations of Driver Information Center buttons. Manual mode can also be entered during the automatic sequence by pressing any button except E/M. Once the display shows Manual Diagnostics, select a module by pressing the OPTIONS button to go forward or the TRIP button to go back. Once a module is selected, a code is displayed, and if more than one are present; press GAGES to go forward or FUEL to go back.
To exit the diagnostic mode at any time, press E/M. If you want to erase codes in a given module, press RESET To reset the codes once in manual mode, press and hold RESET until it displays NO CODES Press OPTIONS to go to the next module. Repeat the steps until you have reset the codes in all the computer modules.
NOTE!! Only reset the codes IF you want to - it is NOT necessary to do this. Clearing a code does not repair a problem. You are simply erasing the evidence of it in the module's memory. If you clear the code/s, and extinguish the Check Engine Light, your emissions status ready will NOT allow you to pass an emissions test until you have completed the required driving cycles. There are a few body module DTC’s that if set will prevent the module from operating properly. Once the DTC is cleared, the module will return to full function. This is not true for power train DTCs.

If you have never read and cleared your codes, there will probably be a lot of old history DTCs. It is recommended that you clear your codes and see if any come back during a driving cycle. Those are the ones that you need to concentrate on diagnosing.

Once you have the codes, the next question is: What to do with the information?
First, consult the factory service manual. Any serious C5 Do-It-Yourself owner should invest in the Corvette Service Manual of the appropriate model year. The Service Manual is really a requirement if you want to understand and work on your C5.

You can read the DTCs while the engine is running. If you turn the engine OFF and then back ON, that can clear some DTCs that may be important with identifying a problem. One example is a Misfire DTC (p-0300) If the engine is shut down, the DTC will clear.

These are some very good C5 Diagnostic Trouble Code (DTC) explanation web sites!!! They also explain how to read the DTCs

Here are some very good sites that explain what DTC mean:

http://www.gearchatter.com/viewtopic11755.php

http://www.obd-codes.com/trouble_cod...d-ii-codes.php

Make sure to include the H or C suffix when you post your DTCs!!

Post what you find.

jhiiidoc

PCM P1571 H C Traction Control PWM link
TCS NO COMMS
RTD C0710 H C Steering Position Signal Malfunction
SDM U1040 H C
RADIO NO COMMS
LDCM B2282 H
B2284 H
B2264 H
U1255 H
U1064 H
U1016 H
U1016 H
U1096 H
RDCM B2283 H
B2285 H
B2265 H

After clearing all the modules, I started the engine and the following codes returned:

PCM P1571 H C
TCS NO COMMS
RTD C0710 H C
SDM U1040 H C
RADIO NO COMMS



So now I'm all

jhiiidoc

OK...guess no help here, huh?

Bill Curlee

TCS NO COMMS is your next thing to fix. Check ALL the TCS fuses. What year C5 and what MODs???

MAKE SURE that the battery is fully charged then, Try to clear the DTCs again using the DIC.

BC

jhiiidoc

2002 A4 F45 Susp
SLP 1.8 Rollers
Diablo Sport Tune from SLP
Cat-back exhaust
C6 Z06 Replicas
Carbon Fiber Hood
ZR Front Bumper
Non Pop-up headlights

This started after the body shop replaced my battery.

For the TCS: Fuses are located under the hood or in the passenger footwell?

Thanks for responding back.

jhiiidoc

Went ahead and checked the fuses under the hood. Checked all the fuses under the hood one by one...all were good.

If it's in the footwell, which one is it?

No comms on Radio...is that because I replaced the head unit with an aftermarket stereo?

Disconnected the battery for 5 min, then reconnected. Same codes set, same messages in DIC.

Even when I try to reset the TCS code, it still says NO COMMS immediately.

Checked the ground point on the driver's side just aft of lights...clean, both the connector and the mount point.

I'm getting ready to send the extra Brake Module I have to ABS Fixer just because I know it will come into play at some point in all of this.

Bill Curlee

Disconnect the battery. Inspect and clean the battery terminals. TORQUE the battery cables on the battery to 11 ft/lbs. Then see if you still have the issue. Clear ALL the DTCs after you connect and TORQUE the battery cables.

BC

jhiiidoc

Removed both battery terminals, checked and cleaned
Checked Voltage before reinstall: 12.3 V
Reconnected Battery to specifications..same messages in DIC return.

Tried to reset TCS....continues to read NO COMMS

Same three codes continue to set after reset.

PCM P1571 H C
TCS NO COMMS
RTD C0710 H C
SDM U1040 H C
RADIO NO COMMS

Bill Curlee

I will find the EBTCM Fuse points. Is your EBTCM rear or FRONT mounted??

BC

jhiiidoc

OK....now you lost me...

EBTCM = Electronic Brake Traction Control Module (I'm guessing)?

It's a 2002, and I have no idea where it is on my Vette.

Bill Curlee

My bad.. It can ONLY be a front mounted unit.

I will send you a schematic for you to check VOLTAGES and Grounds.

BC

jhiiidoc

Are you talking about the piece that sandwiches with the module with all of the brake lines going into it?

jhiiidoc

After the EBTCM thing, I did a google search and found this at DigitalCorvettes.com They give you mad props, by the way

1. Check your ABSTRNS fuse and also your ABS/RTDELEC fuse in the underhood fuse box. Verify that these are good. If they are not replace them obviously.

2. If they are good then Check the ABSTRNS Micro relay in the fuse box. To do this you are going to need to operate the relay. One side will be hot and the other side will go to the relay control sw. in the Body Control Module (BCM). On my vehicle the side to the BCM is at the C2 connector Pin B1 at the fuse box. I have a 1997 so you will want to verify yours is the same or different by pulling the relay and trying to follow the relay coil contacts the opposite side of the battery connection. You will need to ground this side of the relay in order to operate the relay. You can then verify the voltage at the ABSTRNS fuse.

A. If the relay is operating properly you should read battery voltage at the ABSTRNS fuse. If you do not get that voltage verify the relay is bad. It should read between 75-105ohms across the coil. If it doesn't read this replace it. If it does verify the contacts in the relay by removing the relay and put 12 volts across the coil of the relay and then verify continuity across the contacts. If you apply 12 volts to to relay and you do not see 0 Ohms across the contacts the relay is bad and you need to replace it.

3. If the Battery Voltage is at the fuse the relay is good. You will then want to verify that it is getting to the Electronic Brake Traction Control Module (EBTCM). Make sure the ign switch is off and disconnect the Connector at the EBTCM. You will need to operate the relay again and verify Pin A of the cable connector is battery voltage.

A. If the voltage is not there you will want to repair the wiring between the ABSTRNS fuse and the EBTCM. Check the connections at the EBTCM and the Fuse box for good connections. There is also one connector in between these two points that you will want to check. This is located on the passenger side of the engine compartment. It should connect the transmission harness to the foward light harness.

4. If batt voltage is at Pin A. then you will want to verify voltage at Pin D of the EBTCM for Batt voltage.

A. If Voltage is not there wiring between the ABS/RTDELEC fuse and Pin D is bad. No connectors in between these two points. Check the Connection at the fuse box for a good connection.

5. If Battery voltage is there Check resistance between Pin B of the EBTCM Connector and ground. Should be 0 Ohms. If not Ground is bad to the EBTCM. The ground should be located on the passenger side of the vehicle back by the transmission I believe. Verify it is connected and clean the connection.

I am taking a few things for granted but this should work, If it doesn't work let me know what the readings you received are. The other DTC's are rear defogger and HVAC we can look at those after you get this fixed.

A little intimidating for me...I may have to farm this out...

Bill Curlee

Heres the schematic. Check EACH fuse with a volt meter. On top of the fuse are two small holes. There test points. Read each test point to GROUND. You should see battery voltage. Then check your grounds.

It looks like you not getting the correct power to the module. That will/can cause a NO COMMS issue. There are other reasons but we will look at power and ground first.

Bill Curlee

When you do the voltage test,,,,make sure the ignition is ON. Heres a picture of the EBTCM & the BPMV.





Seperated from each other:

jhiiidoc

OK...I have a spare one of those sitting in the garage from the previous warranty fix.

Had a slight mishap with a wrench while installing the idler pulley resulting in a popped ligament in my right wrist...damn painful...I'll get to the fuse checks as soon as it stops hurting to tie my shoes...

espz06

I just now started throwing all these same codes after (hopefully) fixing another issue. When I move the connector to the EBCM (the one with the plastic latch), it goes away.

As soon as it cools down I'm going to check the connector. I hope that's all mine is. Just an FYI and a reminder to check those connectors!