benspeeder

Hello - I'm the proud owner of a 2001 Z06 that is highly modified from East Coast Super Charger. Full head, Cam job, tuned, makes 456HP and 435 TQ at the wheels. Full Pfadt road race setup. Car has an after market radio that works fine. Also has a Viper alarm system.

The car is having the dreaded ABS and Traction Control lights, Service Soon message displayed.

Pulled the following codes while car was running after a drive:
(after clearing all old codes)

10pcm p0102 hc mass air flow circuit low freq - power train control module

10pcm p1571 hc traction control torque request circuit

28 tcs no com

40 BCM b2647 hc light sensor short to ground open - body control module

58 sdm U1040 hc sensing and diagnostic module

Bo Rfa u1064 h remote function actuation

Some observations and sequence of events:

1. Saw the ABS/TC lights for the first time (I've driven it maybe 100 miles since purchased), stopped the car and restarted it - lights cleared.

2. Went on vacation and killed the battery by leaving the radar detector on. The battery would not charge beyond 78% or hold a charge so I purchased a new battery and installed it. This is when the warning lights stayed on every time I started the car. (the radar detector no longer has audio after this, which is coincidental? nah...:-))

3. Did many hours of research on this site which is awesome - hoping the esteemed Bill Curley or others of forum fame and awesomeness see my post :-)

4. Went through all of the grounds, pulled the connectors apart, no corrosion, all grounds look good and tight.

5. Reseated the EBTCM connectors - inspected look good

6. Tested all fuses and volts to fuses - all good

7. My last job is to test the EBTCM plug for continuity and volts - I'm new at the electrical testing but have the schematics and will follow those.


Here are my thoughts on what's busted and hope folks will give me their thoughts:

EBTCM is fried and I will send to ABSFixer to repair

Data serial cable is toast - must figure out where it is and test for continuity (such a newb but I do have a multimeter that I study youtube to learn how to use)

Ignition switch needs to be cleaned - although volts looked good at the engine fuse box 11.8 - 12.2 range

There is a ground wire under the engine fuse box perhaps busted - saw that on several posts

TAC - PCM are dirty or fried - need to confirm their location and take a look

Not being a great mechanic or remotely good at electrical gremlins I thank all of you in advance for any suggestions!

Cheers,

Ben

benspeeder

Thanks 8vette7 - battery tests 12.6 so I will study up on the ignition links!

Much appreciated and you are one of the forum icons of awesomeness

Will post readings on fuses tomorrow

One observation - seems like the issues I experienced occurred for many owners after battery issues. Do you see that trend also and maybe suggest why?

Cheers!

benspeeder

Ps a point I forgot to mention is that the tcs button will not do anything when pressed or held down. Thanks

benspeeder

OK - here's and update

Took car for a spin and checked codes while running - all the same.

1. checked the TCS button - all pins looked good, no corrosion or carbon - it does not "click down" "click up" but from my last Z06 I don't think the button performs like that, just press or press and hold, correct?

2. Went over the battery again. Pulled it and found the negative terminal while screwed in, was stripped. Replaced the terminal bolt. Tested on the bench as 12.4v with the multi meter. Not sure that's out of tolerance while 12.6v is perfect. Comment on that? Bring it back? Can't see that would be the cause but these cars seem a little electrically persnickety. Reinstalled battery.

3. Checked all fuses with car ignition in on position and engine running.

engine fuse block #19, 18,17, were 11.9v engine running 13.9 #22,16, 13 were 11.8v engine running 13.8v Interior block #22, 21, 19 11.7v engine running 13.9 (lights dimming battery a bit when checking in "on" position I figure)

Anything here say ignition needing to be inspected and cleaned?

Appreciate the guidance

ledesordre

10pcm p1571 hc traction control torque request circuit
28 tcs no com
58 sdm U1040 hc sensing and diagnostic module

My car used to have these exact same 3 codes. Results of many months of troubleshooting- My EBCM was toast. Tried to have it repaired by a service like absfixer, and it was still toast. Swapping out a known good EBCM was the only thing that solved my issues. See if you have a friend nearby with an 01-02 Corvette who can swap modules with you to see if it changes your codes. That's what I did and instantly knew the solution.

https://www.corvetteforum.com/forums...571-u1000.html

dadaroo

[QUOTE=benspeeder;1588776359]OK - here's and update

Took car for a spin and checked codes while running - all the same.

QUOTE]

Did you reset/clear the codes before you went for the drive?

3boystoys

Till you solve the 28 tcs no com issue, your paddling upstream.

ledesordre

I agree for sure. I did the same in my thread linked in the post, should give the OP some troubleshooting ideas.

benspeeder

Will post this weekend - going to eliminate the battery and ignition from potential causes but will also start making calls for a new ebtcm or repair

Thanks all

benspeeder

Enjoyed your thread and successful fix - bet mine is the same. Tough to do the ignition?

ledesordre

That took me a couple hours including disassembly of the interior. Surprisingly easy and it also fixed some starting hesitation I had once in a while.

Good luck!
edit: also I searched high and low for a good deal on a replacement ebcm for the 01-02.. most were in the range of $700-1000. the best deal i could find is this one, and it was the one I bought too: plus its amazon, so if it doesn't solve the problem, you can likely make the case for the return.

Bill Dearborn

With that range of codes the first thing to look at is to see if you are getting a solid +12V and a solid ground to the circuits. Check the battery cables where they attach to the battery, check where the battery ground attaches to the frame and check to make sure +12V is getting to the modules and that their grounds are clean/dry at the various frame ground points. If all that stuff is is in good shape then you can move on to working with the codes. The NO Com with the TCS is an indicator of a low voltage problem that is being caused by poor connectivity to the battery and/or ground. The EBCM is located on the opposite side of the engine compartment from its ground point (G108) which is co-located with G104 on the frame below the battery location.

Traction Control light looks like it is being caused by an ECM problem. That is what the P1571 and P0102 codes mean. Fix the MAF sensor issue and the P1571 will go away. It is a code that basically says the failure isn't in the EBCM.

U codes happen all the time on C5s. Very rarely do they point to a problem. The pop up due to state of health messages that are periodically sent from one module to another which don't always get through on the bus due to random electrical interference on the bus. When that happens a U code for the module that didn't get the message is set and isn't reset even if it gets the next message.

Unless something has changed it is doubtful ABS fixer can fix this module. The only repair he can do on the 01-04 modules is replace the relay that is involved with the C1214 failure. There are no parts available to fix the 50 or 60 other failures that can occur within the module. If he swaps your module for one that was on the shelf it is a crap shoot whether or not the module he sends will fix your problem.

I imagine he gets a lot of non failed modules just due to poor diagnostic procedures performed by the car owners. Unless he has a car to plug them into he has no way of testing them so has no idea which ones are truly good or bad.

Make sure you have the proper diagnostic procedures for each code. Codes don't tell you what failed but only where to look for a failure.

Bill

benspeeder

Thanks for the link! I bet that is the fix but will continue with the electrical diagnosis

benspeeder

Thanks for the additional, detailed perspective on how to run down the issues. I'm not convinced my new battery is great and will exchange it. I also need to test volts and continuity to the ECBM itself. All the grounds look fine. Ignition will be inspected and cleaned this weekend.

Can you shine more light on the potential ECM problem? Is there a shop manual I can download that covers the proper diagnostic procedures?

Cheers

benspeeder

UPDATE

Put a new Bosch battery in the car. (The old one tested at the store at 12.43v) Seems like my multimeter tests low as I got 12.0-12.1v.

New battery still tests at 12.4v with my multimeter and was 12.7 at the store.

The pins at the EBCM connector tested low - 11.2v.

So here's the continued plan. Check the grounds AGAIN.

I pulled the EBCM and will see about getting that tested. I am convinced the thing is the problem, despite the low volt readings. Had a '04 Tahoe that had an EBCM failure and ABS fixer did the trick so that is influencing my thought process.

Take apart the interior and do the ignition inspect and clean - really hate taking apart interiors so not liking that job - maybe will get a friend to do it :-)

Will continue to update. My hypothesis is that when the battery goes totally dead and is then charged in the car while still connected to the car, the electrical waves pound the EBCM and fry it sometimes. Seems like a trend of EBCM failure right after a battery issue. Comments?

ledesordre

11.2v.
hrm. I'd start with the ignition switch contacts, for sure. sounds like they are burnt. mine looked pretty bad and I was getting higher voltage than that beforehand. The job isn't TOO bad to dismantle the interior. I've had to do it a few times now so it's nice to see how it all goes together. I've definitely read that it can fix the tcs no comms issue, but I didn't get so lucky.

benspeeder

Agreed. We've got a snowstorm so that might be a project for tomorrow.

I am happy to report that the grounds by the battery tray are now polished and the ground for the ebcm read a perfect 000 :-)

benspeeder

Question - if I buy a new ignition switch would I need to do any reprogramming or just install? Works with the original key?

New is $50 free shipping - worth it to me.

benspeeder

Thanks 8V7 appreciate the details. Ordering one

dadaroo

Here is a link on separating the cylinder from the switch.

https://www.corvetteforum.com/forums...-cylinder.html

Do you need guidance on accessing it?