​​​​​​Hi guys, looking for assistance on troubleshooting an ABS problem that has been kicking my butt for quite some time now. This is on a track car that's only driven to and from tracks. Here is the basic info about the car:

• 2001 ZO6
• AP Racing RadiCAL 355mm (front only, stock rear)
• Ferodo DS1.11 (front/rear)
• Goodridge Stainless Lines
• Motul RBF600
• NT01 315 square (18x10.5)

Problem
ABS light is always on. DIC displays code 1265 (LR Inlet Solenoid Valve Malfunction)

History
Problem started in 2018, as code 1266 (LR Outlet Solenoid Valve Malfunction). It randomly popped up during a track session, then went away on the next ignition cycle. Then, it popped up intermittently until the ABS light eventually came on and never went away. I tracked the car the rest of the season without ABS functioning, then sent the EBCM to ABSFIXER for repair.

I installed the repaired EBCM and the ABS light stayed off. I didn't track the car in 2019 due to needing upkeep/repairs. This year, driving on the street to the first track day, the ABS light popped on. This time, it shows code 1265 (LR Inlet Valve Malfunction). Like last time, it would turn on and off intermittently until it eventually stayed on permanently. When I got back home, I swapped the EBCM over from my other 2001 C5Z that's worked flawlessly. Once more, it worked fine and I engaged ABS a few times with solenoid activation to be sure. Cruising on the freeway for 20min, it randomly popped up again, showing the same code 1265. As always, it became intermittent with each ignition cycle until it stayed on permanently. This brings up to today. My other C5Z is currently in a body shop and I won't be able to swap in the modules to test in that car for a couple days.

My Troubleshooting

• Checked all grounds
• Followed all harnesses/wires to check for damage, mice chewing, corrosion, etc
• Ohmed out all wires of EBCM harness to each pin to make sure there were no dead shorts
• Checked all wires/pins of EBCM harness for anything loose/broken, etc (I did not get down to the base of the pins, the connector won't let loose without breaking the clips)
• Sent EBCM in for repair by ABSFIXER
• Swapped in known good EBCM from same year C5Z

Future Troubleshooting
I'm going to buy a Tech2 so I can run diagnostics on the ABS and cycle valves for testing. A forum member has offered assistance doing this and using an O-Scope. May purchase a used BPMV (found a place selling them with lifetime warranty) and swap in for testing.

Any other ideas or recommendations? Anyone have experience with the ABS system and can assist in troubleshooting?

Thanks guys!

 

- Same error, Instructed to Ship it back to ABSFixer
https://www.corvetteforum.com/forums...abs-fixer.html

- "You may need to replace the BPMV".....
https://www.corvetteforum.com/forums...ease-help.html

There are some more [CF] Search Results utilizing a Google search (for the error)..

 

First, I appreciate at least responding. If you read through the symptoms, you'll see why sending the unit in for repair won't help. I've gone through 3 of them. I already know the BPMV is a troubleshooting option, I typed it above as well.

Troubleshooting the BPMV requires an additional tool that could be purchased to give you pin outs for checking voltage and resistance of the solenoids. Pretty sure I won't be able to get that anywhere, sadly. Just looking for someone who has additional ideas on testing the system.

 

 

The solenoid coils are on/in the EBCM for your year module. That means you swapped the solenoid coils when you swapped the module which points to the mechanical solenoid valve on the BPMV being the issue.

The BPMV pinout adapter is called out for use in the service manuals on 2000 and earlier cars, not 2001+ cars.

 

I installed one of the EBCM's into my C5Z (the car I've never had problems with) and the module is definitely toast. It comes up with the same 1265 error in that car now too, so whatever is going on in the track car is definitely killing these modules.

This is getting expensive fast, and causing substantial downtime. I now have two C5Z's with broken ABS.

Here's what I've learned so far, and things I don't have answers to. If ANYBODY has insight, I'm listening.

1. The EBCM's are NOT THE PROBLEM
2. There could be a wiring issue in the harness or another plug (but if so, why would it only affect the rear solenoid coils..they are internally switched by grounding)
3. There could be sticking rear solenoid valve bodies in the BPMV (but if so, why would it burn up the electrical coil in the EBCM?)

I'm about to buy a Tech2 and a new BPMV, and I'm not convinced it'll get me anywhere at all on this issue.

Is there anybody at all out there that understands these things? A shop? Anyone???

 

From pictures, I would have thought the coils and drivers could be fixed. Take good coils or driver circuit parts off one failed module and replace the failed ones in another module.

Most solenoids will draw a higher current until the plunger moves into the coil. Maybe the solenoid plunger doesn't move and causes the coil to draw excessive current until it fails?

 

It's possible, I was considering it.

But what I struggle with is WHEN it failed. If I was engaging ABS, then I totally agree. But I was literally just driving down the freeway for 30min when the light popped on. Does that make any sense to you? It's what I'm really struggle with. I tested ABS several times with that module (its the one I grabbed from the car that never had problems). So, MAYBE the prior activations on the street (I just panic braked 3 times to see if it worked) weakened the coils until it just randomly failed?

BUT, the module I got back from ABSFIXER, it also worked fine. However, I never got into ABS even once and it still failed. So, if the solenoid coils aren't being energized, how is it failing?