edge04

Anyone have part numbers for Hawk DTC-60's front and rear for C6Z Brembo BBK?

Went to carbotecj X24 fromts and X12 rears and don't care for them so going back to the 60's. Thanks

steel_3d

Don't know if this thread is the right place for troubleshooting questions, but... I've been having a persistent issue with my right front wheel locking up under ABS. Caused flat spotting on track several times, and even on the street. The only code I found in the EBCM was C0221 - Right Front ABS Channel in Release Too Long. Not sure if this is pointing to an issue with the right front wheel speed sensor, or just a symptom of the fact that the wheel locked up. I wasn't able to make the code come back from short lock-up events, so it's kind of hard to diagnose without destroying the tire. The right front wheel speed sensor reads fine on the Tech 2 during normal driving, turns, etc. But the wheel locks up basically any time the ABS should be active. Other wheels are fine.

I'm wondering if it's a bad wheel bearing causing erratic readings under heavy braking load? A problem in the ABS module? Maybe the ABS module could use a bleed? Hasn't been bled in 10 years (brakes have), but I don't have symptoms of air in the system. Anything else you guys might've had experience with related to wheel lock-up issues? Thanks!

mattastick

What pads/tires? Certain pads do not release the same as other pads (Hawks are really bad, for example).

steel_3d

Michelin PS 4S tires and stock Z51 pads. It's been happening with a bunch of different tires. Years ago my ABS was working fine.

Bill Dearborn

ABS module bleed won't affect the lock up. That is nothing more than air in the brake lines which causes the opposite of lock up.

You don't mention what year car you have. I assume it is a C6 due to your avatar picture. However, C6s had two different ABS systems. 2005 through 2008 and 2009 through 2013. The early models got the Delphi Controller and the later models got the Bosch controller.

After looking at the FSM for 2008 and 2009 the code indicates the car is an early model with the Delphi Controller as the Bosch has different codes for the ABS.

Here is the diagnostic procedure for the code. See if you can find what is causing the problem by following the procedure. You probably don't have the test equipment to run the solenoid test as that requires a TECh 2 or equivalent scan tool but everything else requires nothing more than a DVM and a test light.

DTC Descriptors
DTC C0220: Left Front ABS Channel in Release Too Long
DTC C0221: Right Front ABS Channel in Release Too Long
DTC C0228: Left Rear ABS Channel in Release Too Long
DTC C0229: Right Rear ABS Channel in Release Too Long

Circuit/System Description
The system relay is energized when the ignition is ON. The system relay supplies voltage to the valve relay. The electronic brake control module (EBCM) activates the valve relay to supply voltage to the valve solenoids. This voltage is referred to as the system voltage. The EBCM microprocessor activates individual valve solenoids by grounding the valve solenoid control circuits.

Conditions for Running the DTC
• Ignition voltage is greater than 8 volts.
• The system is in a ABS braking event.

Conditions for Setting the DTC
This code is set when the following criteria are met.
• The EBCM is commanding a valve solenoid to release brake pressure.
• The wheel that is commanded to release brake pressure has a speed less than 5 km/h (3 mph) for 1.25 seconds.

Action Taken When the DTC Sets
• The EBCM disables the ABS system.
• The ABS indicator illuminates.
• DRP function is degraded.

Conditions for Clearing the DTC
• The condition for the DTC is no longer present.
• The electronic brake control module (EBCM) automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Diagnostic Aids
• Always diagnose and repair any wheel speed sensor failures prior to diagnosing DTCs C0220, C0221, C0228 or C0229.
• DTCs C0220 - C0229 may be set on surfaces that are nearly impossible to get traction on. If the DTC sets within these conditions, diagnosis of the ABS system may not be necessary.

Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the EBCM.
2. Test for less than 5 ohms of resistance between the ground circuit terminal E and ground.
⇒ If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminals A and B and ground.
⇒ If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test or replace the BPMV.
4. Ignition ON, use the scan tool to perform the solenoid test.
⇒ If solenoid test failed, replace the EBCM.
5. If all circuits test normal, replace the BPMV.

Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• Brake Pressure Modulator Valve Replacement
• Control Module References for EBCM replacement, setup, and programming

Bill

steel_3d

Thanks a lot for the info, Bill! I see that the code will only be set if a wheel locks up for over 1.25 seconds. That's major flat spot territory, so it'll be hard to test. No wet roads here in California

I have an 08 Z51. I also have a Tech 2. I didn't find an ABS test option, only actuating individual solenoids, but I'll look again. Referring to "4. Ignition ON, use the scan tool to perform the solenoid test."

My theory with air in the system was that maybe as you apply the brakes you compress the air enough to effect enough braking force, but when the module tries to release pressure, it doesn't move that much volume of fluid, and the air just takes up the extra space and keeps the pressure on. It's a wild theory, but it could happen depending on the fluid volumes involved.

Bill Dearborn

Air in the BPMV would have been noticed by you every time you stepped on the brake. It feels just like air in the calipers or any other part of the system. Spongy pedal.

Also if the brakes have been bled over the years the valve is bled as well as the fluid has to pass through its channels to get to the calipers. The problem comes when certain valves are closed and air gets caught behind them. Then you have to cycle the valves so that one valve will open and let the air pass through the channel. That only happens if the system has been open to air and the fluid level in the reservoir dropped to the point air was introduced to the master cylinder or the calipers were bled dry and air got into the valve by coming back up system from the calipers. I had that happen once when I was changing brake calipers and hoses and I couldn't get a hose reconnected to the car hard brake line. Lots of fluid on the floor and lots of air in the modulator.

Bill

Quickshift_C5

Experiencing heavy ABS engagement and decreased brake pressure.

froggy47

I am not the expert on this thread, but I do know/experience what ice mode is. Ice mode removes all but about 10% of your braking power which is quite the opposite of being IN ABS mode. You put your foot thru the firewall & nada. To recover ice mode you quickly fully release the brake pedal and reapply, brakes come back. Not sure what you may have been reading about ice mode?

Quickshift_C5

I read that it had decreased brake pressure, but without knowing for sure if I'm experiencing it, I don't know by how much.

So, if it isn't the ice mode, then the next step is figuring out why ABS is coming on so easily and why it feels like the brakes are weaker than they should be. The only thing I've done is the square tire setup and AP brakes. Pedal feels fantastic, and using RBF600 fluid.

froggy47

I am stock brakes, various pads. The only time I get "excessive" abs (regular pedal) is when my tires are shot. So I have excess braking capacity for the tire grip.

Again, not the expert, but on paper it looks like you have too much brake power for the tires. So once your tires say "that's it pal, that's all I got, you are asking for more deceleration (caliper & pad and rotor) than I can handle " your abs does what it should.



Others yes/no/too simple?

Quickshift_C5

I find it hard to believe it's too much brake for a new set of 295x Toyo R888R's, especially when Essex/AP Racing mimics the OEM brake torque to avoid problems. It doesn't make sense. Curious what others think as well. Thanks!

froggy47

Surprised nobody else on this thread today.

Hi Volts Z06

Just a stab in the dark but how old are the tires? If they were new...check date codes to see if they might be old and sitting around for a long time in poor environmental conditions.

Quickshift_C5

Date code on all 4 tires reads "AAM4316", so manufactured roughly in 43rd week of 2016 (Oct 24, 2016). I purchased them this year in May, I believe.

Hi Volts Z06

[QUOTE=Quickshift_C5;1595747272]Date code on all 4 tires reads "AAM4316", so manufactured roughly in 43rd week of 2016 (Oct 24, 2016). I purchased them this year in May, I believe.[/QUOTE

Probably not your issue then. Maybe you just need to get used to modulating this new setup. I used R888's on my 2002 C5 with a Stoptech big brake kit and very aggressive Carbotech XP-16 pads years ago and never had this issue.

Quickshift_C5

It's definitely possible. As I understand it, ABS engagement over OEM shouldn't be any different with this setup. My other C5Z has been using the original R888's for years and was my first track car until I slapped a supercharger on it. Then, bought a BRZ and tracked that for several years before selling it for another C5. The only change are the brakes and 295 square tires (I used OEM sizes on other C5). I'm open to ideas, but I feel it's either engaging ABS far too easily (as opposed to OEM brakes), it's ICE mode, or something is wrong in the ABS system or something causing it to have a false reading.

mattastick

Comparing brakes on a twin to brakes on a C5 (in terms of feel) is hilarious. I had a twin owner autocross my C5 at our last event, and he was complaining about the brake feel constantly. So if you're expecting your C5 brakes to feel like your twin, it's probably not going to happen.

If it's ICE mode, then you're going to have a super hard pedal and almost no deceleration (maybe 10% of what the car is capable of generating). So if you're still slowing down while in ABS, it's not ICE mode.

It looks like the DS1.11 pad has a really hi mu at relatively low temperatures. This could definitely lead to excessive intervention, if you're expecting twin brake like feel (my C5 seems to take a lot less pedal force, but higher pedal travel, to get ABS engagement compared to the twins I've driven). I can get into ABS on my C5 with DS2500s at low temp and those have a much lower mu value than the DS1.11s do.

TLR: If the car is still slowing down while in ABS, you're just asking for too much via high pedal force. Back off the pedal force or squeeze the brakes (rather than slamming them).

KNSBrakes

So say the engine was out and all the lines/MC etc were exposed.

What is the procedure to re-'prime' it?

Ken

ErnieN85

system bleed with a TechII